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  • Life and Medical Sciences  (537)
  • Humans
  • 1930-1934  (365)
  • 1925-1929  (172)
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  • 1
    Digitale Medien
    Digitale Medien
    Masthead (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 40 (1925) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050400201
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  • 2
    Digitale Medien
    Digitale Medien
    Conjugation of paramecium multimicronucleata, powers and mitchell (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 40 (1925), S. 111-167 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Microscopic examination of both living and stained forms indicates that the so-called ‘multivacuolate’ and ‘amicronucleate races of Paramecium caudatum’ belong to the species Paramecium multimicronucleata. The published accounts of the morphology and cultural characteristics of the various forms are compared and provide additional evidence. A more complete description is given, including distinctive characters previously omitted.The conjugation process of P. multimicronucleata in general resembles that of P. caudatum, most of the differences being due to the presence of four micronuclei instead of one. These each divide twice with characteristic figures, twelve of the sixteen daughter nuclei then degenerating. One of the remaining four splits to form a single pair of functional pronuclei in each cell. The two migratory pronuclei interchange as in P. caudatum. The synkaryon divides three times, and probably seven of these nuclei degenerate. The remaining one apparently undergoes two divisions. In most cases by six to eight hours after the conjugants separate two micronuclei of the four thus produced form enlarged macronuclear anlagen, the other two remaining as micronuclei. Each anlage divides within the next two or four hours, producing four macronuclear and four micronuclear analagen. Two fissions, each preceded by a division of the micronuclei, restore vegetative conditions.The process described above is compared with conjugation in P. bursaria, P. caudatum, and P. putrinum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050400103
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  • 3
    Digitale Medien
    Digitale Medien
    Karyosphere formation and synapsis in the beetle, phanaeusThe investigation here reported was carried on in the Zoölogical Laboratory, Columbia University. (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 40 (1925), S. 261-297 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The parasynaptic union of chromosomes associated with the formation of a karyosphere is demonstrated in the spermatocytes of Phanaeus.The twelve V-shaped leptotene threads are polarized with their apices embedded in one plasmosome-like body, their distal ends in another (primary and secondary caps, respectively), and undergo a conjugation of the parasynaptic type. The distal ends of the chromosomes are freed from their attachment in the secondary cap. The six pachytene loops retain their polarized configuration.The basichromatin of the pachytene chromosomes appears ultimately to be withdrawn to form the karyosphere comprising six chromatic bodies within an oxychromatic «plasmosome,» the latter probably derived from the primary cap. The two caps are believed to arise from the chromosomes. The primary cap apparently becomes incorporated again in the chromosomes; the secondary cap, together with linin remnants of the pachytene chromosomes, disintegrates in the nucleus as residual chromatin.In the dissolution of the karyosphere six ring-shaped tetrads emerge arranged in a temporarily connected chain, giving under certain conditions, the misleading impression of twelve components arranged end to end. The entire content of the karyosphere appears to be employed in the formation of the chromosomes; no visible plasmosome remains.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050400204
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  • 4
    Digitale Medien
    Digitale Medien
    The histogenesis of cartilage and bone in the long bones of the embryonic fowl (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 40 (1925), S. 417-459 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The development and cytology of cartilage and bone in the limbs from the fifty-second hour of incubation to the first day after hatching are described.The chief points of interest arising from this study are: (1) Chondroblasts when liberated during cartilage resorption die and disintegrate. (2) All the long bones possess structures which, though not undergoing independent ossification, are homologous with the mammalian epiphyses. (3) Endochondral ossification occurs only in the epiphyses and ends of the diaphyses. (4) The marrow cavity contains multinucleated giant cells which appear to be formed by the fusion of degenerating cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050400302
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  • 5
    Digitale Medien
    Digitale Medien
    The histology of the blood of perophora viridis (ascidian)The observations here recorded were made at the United States Biological Station, Beaufort, North Carolina. I wish to express my gratitude to Hon. Henry O'Malley, Commissioner of Fisheries, for the privilege of using the laboratory, and to Mr. Charles Hatsell, acting director of the station, for the many courtesies extended to me during the course of the work. (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 311-331 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The blood of Perophora viridis is found to contain six types of cells: (1) Green cells, which have green-colored fatty bodies embedded in clear cytoplasm. (2) Orange cells, with orange-colored bodies of unknown composition in the cytoplasm. (3) Colorless berry-like cells, with fluid-filled vesicles in the cytoplasm. (4) Granular amoeboid cells. (5) Compartmental amoeboid cells, which have box-like vacuoles containing brownian granules of a fatty substance. (6) Vesicular, signet-ring type of cell having a single large vacuole. The cytological structure of these cells and their reaction to various dyes are described.An effort has been made to homologize the types of cells found in the blood of other ascidians with those found in Perophora.It is concluded that the variety of colors found in the cells of ascidian blood is due to the varying chemical states of the vanadium-containing chromogen present in the cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410203
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  • 6
    Digitale Medien
    Digitale Medien
    The germ cells of anurans. II. An embryological study of sex differentiation in Rana catesbeiana (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 441-546 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Embryological study of bullfrog tadpoles collected from various parts of the United States has shown the existence of local races which differ markedly in regard to the time of occurrence and character of the developmental processes involved in the formation of the definitive testis of the male individuals. Those races in which the gonads of the two sexes are easily distinguished in early larval stages are called differentiated. Other local races show a peculiar gonadic development chiefly affecting the males, the definitive testis sometimes not appearing until near the end of the second year of larval life. Such races are called undifferentiated, because the morphological features of the definitive testes are not established until late. The larvae first develop a peculiar gonad (progonad) which later degenerates and is replaced by the definitive testis. All male animals of the undifferentiated strains exhibit the gonad cycle.The progonad varies among the local frog races in regard to the length of persistence and degree of differentiation attained before undergoing degeneration. Its germ cells may exhibit a typical male maturation cycle ending in degeneration, or the cells may differentiate along both male and female lines or remain sexually neutral.The development and differentiation of the progonad in the various races are described and a detailed account given of the origin of the definitive testis. The problems of sex differentiation and continuity of the Keimbahn in anurans are discussed.
    Zusätzliches Material: 100 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410207
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  • 7
    Digitale Medien
    Digitale Medien
    Masthead (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050420101
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  • 8
    Digitale Medien
    Digitale Medien
    The metabolic gradients of vertebrate embryos. II. The brook lamprey (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926), S. 111-141 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Disintegration in killing agents was studied throughout development. In the unfertilized egg and cleavage stages the death gradient runs from animal to vegetal pole. In the late blastula stage the future dorsal surface and future point of gastrulation show heightened susceptibility. The gastrula has a gradient from anterior to posterior end along its dorsal surface, with a slight reverse gradient around the blastopore; lateral and ventral regions are least susceptible.Before and after the appearance of the neural groove, the dorsal surface shows increased susceptibility with gradient in it from anterior to posterior end. The neural tube is highly susceptible, with a death gradient from anterior to posterior end and a slight reverse gradient at its posterior end.During late stages and in the larva the double gradient is present; death begins at the two ends and progresses backward from head, forward from anus; from the former most rapidly. The least susceptible place is near the posterior end. The posterior reverse gradient is less developed in the lamprey than in other vertebrate embryos, due, probably, to its lack of a tail bud.Assuming that death differences indicate differences in rate of activity, it appears that such differences in activity may be causes and not results of developmental processes, for the development of certain parts (dorsal surface, blastopore, central nervous system) is indicated by heightened activity before it is evident morphologically.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050420105
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  • 9
    Digitale Medien
    Digitale Medien
    The development of the premandibular head cavities and the relations of the anterior end of the notochord in the chick and robin (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926), S. 371-439 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The prochordal plate in the chick is a thickening of the entoderm in the anterior part of the area pellucida. It consists at first of several layers of yolk-charged cells, which finally lose their yolk and form a thin layer of entoderm.The prechordal plate (an area of mesodermal proliferation immediately anterior to the notochord) arises immediately anterior to the primitive streak (and head process when the latter appears) in a part of the region once occupied by the prochordal plate. Later the prechordal plate comes to lie upon the dorsal wall of the foregut.The premandibular cavities arise in condensations of the prechordal mesoderm. The cavities seem to appear during the rapid expansion of the prechordal mesoderm which occurs in response to a release from constraint imposed by surrounding structures. They are connected with one another across the midline by a usually solid bridge of mesoderm.Later, the cavities are replaced by a mesodermal condensation which serves as a mold, on the surface of which the oculomotor muscles appear, arising before the disappearance of the premandibular head cavities.Differences in the relations of notochord and hypophysis in the chick and robin may be explained by an analysis of the growth of the two forms. The analysis furnishes a basis for understanding the relations of the anterior end of the notochord in the mammal.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050420203
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  • 10
    Digitale Medien
    Digitale Medien
    Masthead (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1926) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050430101
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  • 11
    Digitale Medien
    Digitale Medien
    The structure and division of paramecium trichium stokes (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1926), S. 81-103 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Paramecium trichium varies from 50 μ to 105 μ long with most individuals between 80 μ and 90 μ. The width varies from one-third to one-half the length. It is somewhat depressed dorsoventrally. The broad buccal groove extends from the anterior left border diagonally across the ventral surface to the mouth, which is usually slightly anterior to the middle and to the right side of the median line. The mouth leads into a relatively long cytopharynx containing an undulating membrane. The cytopyge is subterminal and the small caudal tuft of longer cilia is subapical. The plastic ectosarc contains numerous trichocysts. A contractile vacuole apparatus occurs near either end. Each is deeply located and stains more intensely than surrounding protoplasm. In life there appear to be two alternately contracting vacuoles with smaller ones adjacent. Contractions are from fifteen to twenty-five per minute. The macronucleus is medium in size and the single micronucleus is of the ‘caudatum’ type.Binary fission appears to be initiated by a metaphase-like condition of the micronucleus. This is followed by great enlargement and the eventual separation of the chromatin threads into two anaphase groups. The metaphase thus appears to precede the changes which correspond to a prophase in other cases. During division of the body, the two old contractile vacuoles persist as the posterior ones for the daughters, new anterior ones being developed.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050430105
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  • 12
    Digitale Medien
    Digitale Medien
    Masthead (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1927) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050430201
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  • 13
    Digitale Medien
    Digitale Medien
    Some cytoplasmic structures in the male germ cells of gelastocoris oculatus (Toad bug) (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1927), S. 299-345 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The chondriosomes are first recognizable as two clusters in contact with the nuclear wall. Beneath each cluster lies a chromosome. This relationship is constant and indicates that these two chromosomes play a part in the growth and development of the chondriosomes. The two masses fuse and the single mass grows considerably during the early growth period. Later it breaks up into a number of threads which become rings in the late growth period. The rings fuse into the large nebenkern which plays the usual rôle in the formation of the tail.The Golgi material is first seen outside of the chondriosomal cap. Early in the growth period, it breaks up into Golgi bodies which remain distributed in the cytoplasm during the growth period and spermatocyte divisions. About the midgrowth period a large number of spheres suddenly arise. Since they later fuse to form the idiosome, they are called the proidiosomal spheres. These spheres, which may originate in the Golgi bodies, remain scattered in the cytoplasm during the growth period and spermatocyte divisions. In the spermatid the Golgi bodies collect about the idiosome to form the acroblast. The Golgi remnants pass into the cytoplasm of the tail, while the acrosome elongates into a tail-like structure at the anterior end.The centriole was followed with unbroken continuity from the midgrowth period into the middle-piece of the sperm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050430204
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  • 14
    Digitale Medien
    Digitale Medien
    Freezing and survival of insects at low temperatures (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1927), S. 521-546 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The literature on the general subject of freezing and survival both in plants and in animals is briefly reviewed and a bibliography given. Insects representing three ecological groups, (1) the oak borers - exposed to temperature extremes normally; (2) stored-products insects representing supposedly a tropical or subtropical group, and, (3) aquatic insects never exposed to temperatures lower than 0°C., were chosen for this study. Determinations of the freezing and undercooling points were made during the yearly cycle.Both the stored-products insects and the aquatic insects studied showed no periodicity in freezing or undercooling. The oak borers showed marked periodicity. The freezing-point varies directly with the moisture content. Cold-hardiness was produced experimentally by, (1) exposure of insects to low temperatures and, (2) by dehydration. Loss of cold-hardiness was produced experimentally by combinations of high temperature, food, and high relative humidity. The freezing-point ordinarily found corresponds with that of the blood. Repeated freezings of the same insect or tissue showed no hysteresis. There exists in certain insects a secondary freezing-point below that ordinarily found. Oak borers in summer condition die at the first freezing-point; in fully hardened condition they die at the secondary freezingpoint.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050430209
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  • 15
    Digitale Medien
    Digitale Medien
    Ant-mounds as to temperature and sunshine (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 1-20 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ant Formica exsectoides F. builds mounds with some reference to sunlight, and measurements of internal temperatures have shown them higher in upper parts of the mound, but different in different faces of the mound - all higher than the earth outside the mound.Inside temperatures are not constant; they are due to the sunshine. The mound is so fabricated that the internal temperatures are conserved during the night. The ants make use of the differential internal temperatures for rearing broods.Some mounds show bilateral symmetry dependent upon sun exposure.Measurements of rate of running of these ants show a falling off with lower temperatures, and possibly this is one factor in the smaller development of northerly aspects of these mounds.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440102
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  • 16
    Digitale Medien
    Digitale Medien
    Oxygen consumption of individual pupae during metamorphosis (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 313-339 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The rates of oxygen consumption of single pupae of blowflies (Phormia terraenovae, Phormia regina, Lucilia sericata), of the flesh fly (Sarcophaga sarracenioides Aldrich), of the Mediterranean flour moth (Ephestia kuehniella), and of the bee moth (Galleria mellonella) during metamorphosis, until emergence, have been determined. The record for each pupa, with the exception of those of blowflies, is practically continuous day and night during the period of pupal development which lasted from 140 to 300 hours, according to the species, at the temperatures used. During pupal development there is first a period of decrease in rate, which is later followed by a steady increase until a short time before emergence, when a sudden decrease occurs.The ‘oxygen curves’ of the blowfly pupae (Diptera) are quite different from those of the flour-moth and bee-moth pupae (Lepidoptera), although all are of the same general U-shaped type. There are strong indications of a specific difference in the curves of the blow-fly pupae. The flour-moth pupae curves differ slightly from those of the bee-moth pupae. During the major part of development the rates of O2 consumption of pupae of both sexes of bee moth and flour moth are about the same, but near the end of metamorphosis the females have higher rates than the males. No such sex difference appears among the dipterous pupae used.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440205
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  • 17
    Digitale Medien
    Digitale Medien
    Factors involved in encystment in the ciliate didinium nasutumThis paper and a preceding paper (Beers, '26) were submitted to the Board of University Studies of the Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy. This investigation was undertaken at the suggestion of Prof. S. O. Mast, to whom the writer is much indebted for valuable advice and criticism, both in the experimental work and in the preparation of the manuscript. He is also under obligation to Prof. H. S. Jennings for helpful criticism in the revision of the manuscript. (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1927), S. 499-520 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The results of the study of certain factors which affect encystment in Didinium nasutum indicate the following: Absence of food constitutes an adverse environmental condition which induces encystment in approximately 50 per cent of the didinia subjected to it, though the presence of a certain amount of food in the cell body is requisite for encystment. The prevention of encystment for 750 generations does not affect the percentage of didinia which encyst in the absence of food, and hence Didinium does not become progressively more disposed to encystment as generations pass. Conjugation does not affect the percentage of didinia which encyst in the absence of food. Metabolic by-products of Paramecium inhibit encystment to a striking degree when didinia are deprived of food in the presence of these products. Metabolic waste of Didinium markedly facilitates its encystment in the absence of food. Hay-infusion culture fluids of different ages have singularly diverse effects on the encystment of didinia in the absence of food; recently prepared infusions inhibit encystment; infusions four to six days old induce encystment in 90 to 100 per cent of the specimens, and infusions seven to fourteen days old, in approximately half of the specimens.
    Zusätzliches Material: 8 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050430208
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  • 18
    Digitale Medien
    Digitale Medien
    The significance of hemal nodes (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 89-115 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The investigation is based upon hemal nodes of dog, man, and sheep. The material can be arranged in a regressive series leading from a typical lymph node, except for the occurrence of blood in parenchyma and sinuses, to a lymphoid structure at a late stage of involution. These structures uniformly lack lymphatics. There is no evidence of direct luminal connection between the blood-vascular supply and the sinuses. The observation that certain cervical and subcutaneous lymph nodes of the rabbit undergo a myeloid metaplasia following atrophy and disjunction of their lymphatics is used as an explanatory key of hemal nodes. According to our view, hemal nodes represent stages in the involution of transient lymph nodes. Disjunction of the lymphatics leaves the sinuses filled with entrapped lymphocytes. These differentiate into erythrocytes. These red blood cells may disintegrate and pass into solution or be removed either by giant cells or mononuclear phagocytes. Late stages in this process are represented by small irregular masses of lymphocytes, with wide sinuses practically free of blood.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440105
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  • 19
    Digitale Medien
    Digitale Medien
    Masthead (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440101
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  • 20
    Digitale Medien
    Digitale Medien
    The development of the eye muscles of the chick (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 29-87 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The anlage of the abducens musculature appears first at 24-25 somites as a condensation situated dorsal to the mandibular arch.The anlage of the superior oblique grows forward from a mesodermal condensation situated in the maxillomandibular region, termed for convenience the maxillomandibular condensation. This last consists of three parts: (1) the anlage of the superior oblique: (2) the anlage of the abducens musculature, and, (3) an intermediate region.The intermediate portion of the maxillomandibular mass forms a condensation with which the anlage of the abducens musculature fuses. Its fate is, therefore, similar to that of the so-called ‘muscle E’ of elasmobranchs, which has been described as fusing with the lateral rectus. How much muscle is formed from the intermediate condensation in the chick has not been determined.The development of the pyramidalis and quadratus nictitans muscles, derivatives of the abducens complex, is described.The premandibular head cavities are replaced by solid mesodermal condensations, on the surface of which the anlagen of the oculomotor muscles appear. The premandibular mass expands laterally and anteriorly over the bulbus, carrying the oculomotor muscles to their respective positions on the bulbus.Portions of the premandibular and maxillomandibular condensations not involved in eye-muscle formation take part in the formation of choroid and sclera.The growth shiftings of the eye muscles are analyzed. The order of their appearance is commented upon.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440104
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  • 21
    Digitale Medien
    Digitale Medien
    The prenatal skull of the Canadian porcupine (Erethizon dorsatus) (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 127-216 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study represents the first critical investigation on the development of the embryonic skull of the porcupine. A complete series of stages makes it possible to trace the developing chondrocranium from its first formation in precartilage to its later transformation into cartilage bone. Concurrent with this growth is the investment of the cartilaginous cranium by membrane bone.The very primitive nature of the chondrocranium offers an excellent opportunity to discuss the existing problems of the embryonic skull from a new angle. Evidence is presented in support of the assumption that the ala temporalis is the homologue of the cynodont epipterygoid. The lamina parietalis develops from a single chondrifying center, thus producing a different arrangement of parietal elements from that found in most mammals. New evidence as to the relationship of the dens epistrophei and basal plate is presented. The position of the internal carotid artery on entering the cranium is different from the condition found in most mammals and throws new light on the interpretation of surrounding structures. The presence of a structure comparable with the crista longitudinalis of Lacerta shows close affinity to the solum nasi of more primitive forms.The great specialization of the face is seen in the early and rapid growth of the membrane bones. The chondrocranium is long persistent and cartilage bone appears late in embryonic life.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440202
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  • 22
    Digitale Medien
    Digitale Medien
    Masthead (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440301
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  • 23
    Digitale Medien
    Digitale Medien
    Studies on the Balantidium from the guinea-pig (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 417-465 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Observations indicate that this Balantidium from the guinea-pig is Balantidium coli, the form found in the pig and man. The lengths and breadths of this Balantidium and the ratios of length to breadth are very close to the measurements and ratios given by McDonald for B. coli. When plotted, the body lengths of the guinea-pig parasites appear in two groups, the smaller individuals being the exconjugants. Many of these exconjugants resemble Neiva's B. caviae. The structure of the Balantidium from the guinea-pig is essentially identical with that of B. coli as given by McDonald.Fission and conjugation of this ciliate follow the general course found in a number of other ciliates. During fission the micronucleus divides and the daughter micronuclei migrate to each end of the macronucleus before the latter divides. In conjugation there are two divisions of the micronucleus, one of these nuclei dividing to form the pronuclei. Pronuclear exchange and fusion are followed by a heteropolar division of the synkaryon, resulting in the formation of the new macronuclear and micronuclear anlagen.The parasite was found in the intestinal tissue of the host. No reproductive stages were found in the cysts. New hosts are invaded through contamination of the food and drink with the cysts.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440304
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  • 24
    Digitale Medien
    Digitale Medien
    A comparative study of the chromosomes of the Norway rat (Rattus norvegicus ERXL.) and the black rat (Rattus rattus L.)This paper (with another study to be published later) was submitted to the faculty of the Bussey Institution, Harvard University, in partial fulfillment of the requirements for the degree of Doctor of Science. It was prepared under the direction of Dr. W. E. Castle. Acknowledgment is due Prof. T. S. Painter for advice on technique and the examination of some of the material herein presented. (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 515-538 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: By the use of a satisfactory technique, excellently preserved spermatogenetic tissue was had both for Rattus rattus and Rattus norvegicus. The careful examination of twelve spermatogonial cells of the former species and of twenty in the latter species shows that R. rattus has forty diploid chromosomes and R. norvegicus, forty-two. A careful examination of the haploid cells of both species, both in the first and in the second spermatocyte divisions, confirms the diploid determinations.Both species have an unequal pair in the spermatogonial divisions and the finding of a similar unequal pair in the first spermatocyte division constitutes the evidence for an X-Y mechanism in each. A comparison of the morphology of the first spermatocyte tetrads in the two species reveals the presence of a large K-shaped chromosome in R. norvegicus which is not present in R. rattus. Furthermore, a comparison of the X-Y complex in both the spermatogonial and first spermatocyte divisions shows that these are morphologically different in the two species, the Y in particular being markedly dissimilar in size. A short discussion as to the bearing of these findings on the questions of the origins of the two species and their known intersterility is presented. The marked similarity of the tetrads of the black rat to those described for the mouse is noted.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440306
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  • 25
    Digitale Medien
    Digitale Medien
    A study of the chromosomes in meiosis, fertilization, and cleavage in the grasshopper egg (orthoptera)A thesis in zoölogy presented to the faculty of the graduate school of the University of Pennsylvania in partial fulfillment of the requirements for the degree of Doctor of Philosophy. (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 45 (1928), S. 47-96 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A technique is developed whereby the large heavily yolk-laden grasshopper egg may be sectioned for cytological study. Eggs of Chortophaga viridifasciata and Circotettix verruculatus were examined.In C. viridifasciata the structure of the late ovarian nucleus and the chromosomes in meiosis, fertilization, and early cleavage are described. In the first maturation twelve rod-shaped tetrads are found. Near the caudal end of the egg a polar body is given off, and in the second maturation division there are twelve dyads. At fertilization, twelve separated vesicles of the female pronucleus are seen scattered about a male pronucleus in which the chromosomes are in prophase.In early cleavage the chromosome numbers in the metaphase are found to differentiate the male- and female-producing eggs. In the former there are twenty-three and in the latter twenty-four chromosomes. A vesicular condition in which the chromosomes retain their boundaries in interkinesis is indicative of chromosome individuality.A comparison of the first and second maturation metaphase chromosomes of the oocyte with those of the spermatocyte shows a similar compact group on the spindle, a likeness in size seriation, and a similarity of form. They differ in that in the spermatocyte complex there are eleven tetrads and one dyad. This latter, the unpaired sex chromosome, falls among the large chromosomes.A comparison of the chromosome complex of Chortophaga viridifasciata with that of Circotettix verruculatus indicates constancy of generic differences in form, size, number, and behavior of the chromosomes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050450103
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  • 26
    Digitale Medien
    Digitale Medien
    Cytoplasmic constituents in the developing egg of Discoglossus pictus Otth (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 45 (1928), S. 233-257 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cytological and histochemical evidence presented in this paper shows the following facts: (1) The mitochondria are not directly transformed into yolk. They may be concerned in its synthesis in so far as they are a factor in the interacting cytoplasmic system, but there are no visible morphological expressions of this functioning. (2) The accumulations of aequeous substances in the cytoplasm in the form of droplets stainable vitally by neutral red, ‘vacuoles,’ are the forerunners of the first yolk. During the building up of the yolk the aequeous droplets become more and more dehydrated and lose their capacity for being vitally stained. (3) These aequeous vacuoles give the impregnation results commonly ascribed to the Golgi apparatus and are interpreted as such. Special emphasis is laid on the question of the identification of the Golgi apparatus. (4) The fat arises de novo in the cell independently of the mitochondria or the vacuoles. It becomes dispersed throughout the cell among the yolk plates, and the lipoidal content of the latter increases at the end of vitellogenesis, when the fatty globules are intimately pressed in among the yolk plates. (5) At a late stage in the growth of the yolk plates there is the sudden appearance of large quantities of glycogen in the perinuclear zone and throughout the cytoplasm.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050450108
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  • 27
    Digitale Medien
    Digitale Medien
    The septomaxillary. I. In the amphibia urodelaThis paper is no. 148 of the contributions from the Department of zoölogy of Smith College. (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 45 (1928), S. 441-471 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The septomaxillary bone is described in the various families of the urodeles in which it occurs. Its identity as a hitherto unrecognized cartilage bone of the skull is established and its close relationship with the nasal muscles followed through the group. Its presence or absence, which is found to be another criterion for the recent classification of the urodeles as proposed by Dunn and Higgins, is correlated with the development of the accessory dilatator muscle, since it occurs only in groups where this muscle attains an appreciable size.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050450203
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  • 28
    Digitale Medien
    Digitale Medien
    The morphology and physiology of the invertebrate liver and hepatopancreasFrom the Division of Experimental Surgery and Pathology. (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 45 (1928), S. 537-554 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Modifications of the gastro-intestinal tract of Nereis virens are two dorsolateral esophageal cecums, directed anteriorly and posteriorly from the point of attachment. The cecal and esophageal lumina are continuous. Each cecum is composed of acini, possessing a row of elongated cells, basement membrane, and intima. Fibro-elastic tissue is present. The elongated cells contain glycogen and fat.The hepatopancreas of Asterias vulgaris consists of two lobes in each ray, and the numerous acini empty into the bifurcated hepatopancreatic duct which leads into the pyloric stomach. The hepatic cells are columnar and contain glycogen and fat. Pancreatic cells lie in the midregion of the acini.The lobulate liver of Loligo pealii lies on the ventral surface of the duodenum. A capsular membrane envelops the organ. The acini possess basement membrane, columnar cells, and intima; their lumina anastomose, forming a common duct, which leads into the blind sac. The hepatic cells contain fat.The hepatopancreas of Melanoplus femur-rubrum consists of six cecums histologically continuous with the digestive epithelium of the pyloric stomach. Each cecum consists of simple and compound acini which empty into a duct leading to the pyloric stomach. Each acinus possesses basement membrane, columnar hepatic cells, pancreatic cells, and intima. The pancreatic cells occur in islets, usually adjacent to the basement membrane. The hepatic cells contain glycogen and fat.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050450206
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  • 29
    Digitale Medien
    Digitale Medien
    Masthead (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 46 (1928) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050460101
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  • 30
    Digitale Medien
    Digitale Medien
    Prenatal growth of swinePaper from the Departments of Genetics (no. 85) and Veterinary Science, Wisconsin Agricultural Experiment Station, in cooperation with the Animal Husbandry Division of the U. S. Department of Agriculture. Published with the approval of the director of the Station and the chief of the Bureau of Animal Industry, U. S. Department of Agriculture. (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 46 (1928), S. 59-84 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Fetuses from forty-three gravid uteruses from sows of known breeding dates, as well as from 448 uteruses with unknown breeding dates, were studied. Growth curves are given for weight and length of fetus and for weight of fetal membranes. The weight of the fetus first reaches that of the fetal membranes between the sixtieth and seventieth days of pregnancy. Degenerate fetuses were found in 3.68 per cent of the cases. They were found at all stages of gestation. Size of litter was found to decrease from 11.4 at the twentieth day to 6.8 at the 110th day. Also, the calculated per cent of ova lost up to each ten-day stage tends to increase as gestation advances. Crowding was found to be an important factor, but probably not the only factor, in causing degeneration. Genetic factors were probably responsible for part of the resorbing fetuses.In the study of the normal fetuses, significant correlations were found between fetus length and weight of fetal membranes, as well as between fetus weight and weight of fetal membranes. Lower correlations, but probably significant, were found between total distance (spacing) between fetuses in the uterus and weight of fetal membranes. Correlations between size of fetus and total distance between fetuses were very low. As in the case of the degenerates, crowding has an important relationship to size of fetus, but is probably not the only factor involved.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050460103
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  • 31
    Digitale Medien
    Digitale Medien
    Masthead (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 46 (1928) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050460201
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  • 32
    Digitale Medien
    Digitale Medien
    Ecological studies of the seasonal distribution of protozoa in a fresh-water pondA thesis in zoölogy presented to the faculty of the Graduate School of the University of Pennsylvania in partial fulfillment of the requirements for the degree of Doctor of Philosophy. (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 46 (1928), S. 431-478 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study deals with the seasonal distribution of protozoa (February, 1927, to February, 1928) in correlation with seasonal fluctuations of temperature, hydrogen-ion concentration, and the relative amounts of dissolved oxygen and other gases in a small fresh-water pond. Twenty-seven species of Sarcodina, thirty-one species of Mastigophora, and 109 species of Infusoria were recorded in the surface water of the pond.As found especially for Mastigophora and Infusoria, the number of species is inversely correlated with the abundance of individuals in the seasonal distribution.Higher temperatures probably accelerated the rate of reproduction, since the seasonal maxima for most of the species were recorded in warmer weather.Colonial flagellates and Zoochlorellae-bearing ciliates seemed to be favored by higher oxygen content, with a simultaneous abundance of volatile acids, especially CO2. Although hydrogen-ion concentration was limited between 6.2 and 7.05, it was probably one of the factors influencing protozoan distribution, since several species disappeared when the lowest pH was recorded. Sunlight is one of the important factors in bringing certain heliotropic protozoa to the surface.The seasonal maxima of many of the protozoa occurred during September and October, 1927, when most of the observed physical environments seemed much more favorable than in other months.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050460204
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  • 33
    Digitale Medien
    Digitale Medien
    The anatomy of the urinogenital organs of the male Myrmecobius fasciatus (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 46 (1928), S. 563-583 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The urinogenital organs of Myrmecobius fasciatus conform to the marsupial type in both their anatomical characters and histological details. The external genitalia indicate a close relationship with the Dasyuridae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050460207
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  • 34
    Digitale Medien
    Digitale Medien
    On the development of imaginal buds in normal and mutant Drosophila melanogaster (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 135-199 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Definite information concerning the time of development and location of the different imaginal discs of Drosophila melanogaster was needed in order to interpret especially the gynandromorphs, mosaics, and intersexes that have been extensively reported in cultures of this fly. This information was also desirable for many of the mutant types. It was not known, for example, when an organ was reduced or absent, whether its imaginal disc showed a corresponding reduction, or whether it was full size in the larvae and pupae, and failed to carry through to the later stages.Three mutant types with eyes smaller than those of the wild type, namely, lozenge, bar, and eyeless, were examined. It was found that there is a corresponding difference in size as far back as the imaginal disc could be detected. Similarly for the two mutants, vestigial and no-wing. Conversely for the mutant, bithorax, in which the metathorax is larger than the normal and has assumed many of the characters of the normal mesothorax, the imaginal disc was correspondingly enlarged.It follows that the effects of the mutant genes for these characters can be observed in the very earliest condition of the imaginal disc.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050470105
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  • 35
    Digitale Medien
    Digitale Medien
    The somatic chromosomes of the opossum (Didelphis virginiana) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 201-225 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: There are eleven pairs of chromosomes in the somatic cells of the opossum.The sex chromosomes are of the x-x type in the female and the x-y type in the male.The number and type of the chromosomes are constant in the wide variety of tissues and organs studied, except that one dividing giant cell of the spleen showed an 8n number of chromosomes.The arrangement of the chromosomes in equatorial plates is that of an autosomal ring surrounding the centrally located sex chromosomes.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050470106
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  • 36
    Digitale Medien
    Digitale Medien
    The neutral-red reaction (1930)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 45-137 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A general survey of the reaction of neutral red upon a selected series of living animal organisms is made, and the rationale indicates that neutral red is an indicator of proteolytic enzyme action, whether this be intra- or extracellular. Cellular hydrolytic and cellular synthetic systems are thus manifested. The neutral-red reaction also reveals the course of assimilation and secretion in organisms, the nature of fertilization, and the beginning of embryological differentiation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050490103
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  • 37
    Digitale Medien
    Digitale Medien
    Masthead (1930)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050490201
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  • 38
    Digitale Medien
    Digitale Medien
    The formation of the sex glands and germ cells of mammals. IV. Continuous origin and degeneration of germ cells in the female albino rat (1930)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 333-353 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The current view in mammals is that ova are formed in the embryo in large numbers and stored in the ovary as a reserve to be drawn on through adult life; they may persist for long periods ina latent condition, a few resuming active development at each recurring oestrous period; new ova are not and cannot be added.An alternative hypothesis has been presented by several authors: New ova are formed throughout life, from the embryonic period through the time of sexual maturity; each ovum so produced must at once begin its growth and development of die; long latency of oocytes and primary follicles is not possible and does not occur. There is a constant degeneration of most follicles, and only a few come to ovulation. A study of the albino rat presents evidence which is consistent with the second view and supports it more strongly that it does the older hypothesis. Similar evidence is found in other mammals. It seems probable that the newer hypothesis is the correct one, at least in some mammals; further investigation may show it to be of general application.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050490203
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  • 39
    Digitale Medien
    Digitale Medien
    The influence of thyroid deficiency on the structure and epinephrin content of the adrenal gland of the albino rat (Mus norvegicus albinus) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 45-79 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: It was found that thyroid deficiency in the albino rat (Mus norvegicus albinus) is followed by a trend to increased concentration of epinephrin in the suprarenals. The basis of this lies in the relatively greater retrogression of the cortex as contrasted with the medulla which becomes a relatively greater proportion of the organ as a whole. Confirmatory evidence is found in cell counts per unit area and the part of the disappearance of lipoid from the cortical cells of the suprarenals of thyroidless animals.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480103
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  • 40
    Digitale Medien
    Digitale Medien
    Growth and maturation in the parthenogenetic and sexual eggs of Moina macrocopa (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 123-151 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: From a study of over 1000 mothers, the female chromosome number appears to be 2N = 22; N = 11. The male number has not been exactly determined, but is presumably not haploid. Only one maturation division occurs in the parthenogenetic egg, and the authors have seen only one in the sexual egg. During the growth stages of the eggs, the chromatin is totally obscured by a large amount of deeply staining nucleolar material which exhibits several phases. Ultimately, this material is apparently absorbed into the ooplasm. Just before the egg is laid, the ovoid chromosomes, in late prophase or in metaphase, are seen in a germinal vesicle situated always at one side of the egg. The maturation division occurs immediately after egg laying. A degenerate body, hitherto undescribed, is noted in the ripe parthenogenetic egg, situated at the pole opposite the germinal vesicle. It is believed to arise by reorganization of nucleolar substance. The body in the sexual egg desribed by Weismann and Ishikawa ('91) as the Paracopulationzelle is noted and its interpretation by these authors questioned, but, for lack of sufficient evidence, no counter-explanation is offered. The possible relation between experimental sex control and the time of maturation division in the parathenogenetic egg is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480106
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  • 41
    Digitale Medien
    Digitale Medien
    Studies in the origin of yolk. IV. Ogenesis of Periplaneta americana (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 253-279 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Technique. This work is based not only on the fixed preparations, but also on fresh cover-slip preparations treated with neutral red or 2 per cent osmic acid for a short time.Golgi elements and fatty yolk. The Golgi elements are hollow vesicular bodies with a distinct osmiophilic rim and a central osmiophobic substance. In the youngest oocyte they form a circumnuclear ring. Gradually the vesicles spread out, grow in size, store up fat in their interior, and give rise to the fatty yolk. On account of their higher refractive index, due to the presence of fat, the Golgi vesicles can be occasionally seen even in the young oocytes without any treatment.Mitochondria. The mitochondrial granules also form a circumnuclear ring and are later distributed uniformly.Albuminous yolk. The albuminous yolk is nucleolar in origin. Early in oogenesis, the nucleous buds off small, homogeneous, and highly chromatic particles in the cytoplasm, which sooner or later disappear. Subsequently, the nucleolus becomes less chromatic and develops vacuolar bodies in its interior, which, becoming vacuolated exactly like the parent nucleolus, migrate into the the cytoplasm. These bodies become more and more chromatic and travel toward the periphery of the egg, where they grow in size. Ultimately they break down into small, homogeneous, and highly chromatic bodies which are the definitive albuminous yolk spheres and which subsequently grow enormously in size.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480109
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  • 42
    Digitale Medien
    Digitale Medien
    Maturation of the male germ cells in the ratAided by grants from the Committee for Research in Problems of Sex of the National Research Council, administered by Prof. Herbert M. Evans, to whom the author is greatly indebted. (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 433-443 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Maturation of the male germ cells in the rat shows some slight modifications of the typical procedure in sex cells, a distinct and rather prolonged synapsis occurring before synizesis and a confused stage immediately after it. The clumping in synizesis is not extreme. In the mixed strain of rats both twenty-one and thirty-one tetrads appear in the late diakinesis. This procedure in the male resembles the maturation of the oocytes in only two points, the beginning of the process, the deutobroch nuclei, and the end of it when the haploid number of chromosomes take their places on the spindle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480206
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  • 43
    Digitale Medien
    Digitale Medien
    Some phases in the embryonic development of Diacrisia virginica fabr. (Lepidoptera) (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 493-541 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cells of the blastoderm which are to form the serosa are two- to four-nucleate; the smaller cells of the embryonic rudiment, uninucleate. The band-like embryonic rudiment encircles the yolk at the equator of the egg. The amnion does not begin to form until after the serosa completely covers embryo and yolk. The epithelium of the midgut arises from cells situated at the tips of stomodaeum and proctodaeum. These cells, though not differentiated from adjacent ectoderm at the time of the invagination, are nevertheless interpreted as part of the preprimordium of the endoderm. In the eighty-four-hour stage a fold of amnion grows over the dorsal side of the embryo, entirely covering it in the course of the next few hours. A portion of the amnion thus forms the dorsal wall of the embryo. At the completion of the amnion the embryo rotates so that its ventral side is directed toward the egg center. The amnion raptures just before the larva begins to feed on the yolk which still remains around it. The serosa is consumed before hatching, which takes place about five and one-half days after deposition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480209
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  • 44
    Digitale Medien
    Digitale Medien
    A histological study of the colic caeca in the bantam fowl (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 585-609 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The caeca of fourteen bantam fowls have been studied. These fowls ranged in age from six days' incubation to three years after hatching. Between the fifth and sixth days of incubation rectal caeca arise as evaginations from the intestine at the junction of the ileum with the colon. The develoing caeca closely resemble histologically the intestine to which they are attached.The caeca are essentially devoid of content until about the nineteenth day of incubation, but during the remaining days of incubation are gorged with a bluish-gray material similar to that found in the colon. Thus, an early defecatory function is indicated.In general, the proximal third of the caeca remains histologically similar to the intestine, but the distal two-thirds undergoes regression. The latter involves the atrophy of the epithelium and glands, accompanied by the appearance of lymphoid tissue. Much of the lymphoid tissue eventually disappears, to a large extent by atrophy and dissolution of the leukocytes. However, to some extent, lymphocytes develop into granulocytes which escape with other leukocytes into the lumina of the caeca and there disintegrate.Lymph nodules begin to appear in the caeca about one week after the chick hatches. The leukocytes, at least in part, arise in situ from the reticular stroma. Eosinophils arise in certain areas of the tunica propria, and in the earlier stages of their development resemble large lymphocytes, in the cytoplasm of which basophilic, amphophilic, and acidophilic granules are intermingled.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480212
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  • 45
    Digitale Medien
    Digitale Medien
    The morphology of the palmar digital triradii and main linesContributions from the Department of Zoölogy, Smith College, no. 159. (1930)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 153-221 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A study is made of the morphological types of the second, third, and fourth interdigital patterns of the human palm and their differential occurrence as a basis for determining the morphological significance of the digital triradii and main lines, which are the final remnants of the pattern boundaries. Certain types of patterns show a large preponderance, with a correspondingly large percentage of a certain morphological value for each digital triradius, although other morphological possibilities than the usual one are discovered in each case. Correlated combinations of rare patterns are presented and their hereditary nature discussed.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050490105
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  • 46
    Digitale Medien
    Digitale Medien
    Studies on some physiological functions and morphological characters of Rhabditis (Rhabditidae, nematodes) (1930)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 251-275 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Intravitam stains were used to determine the functions of several organs in two species of nemas (Rhabditis strongyloides and Rhabditis elongata). The organs were also studied in section. From the results obtained it is concluded that the amphids are not excretory in function, but more probably sensory, for definite connections were observed to extend to the nerve ring. No migratory cells, such as those described by Stefanski, were seen.The phasmids stained with all intravitam stains used. but were never observed to secrete. It seems doubtful that they serve as excretory organs.The excretory system was seen to consist of a typical X system. Actual excretion was observed. Deirids were seen for the first time in both species. Oesophageal glands were also described. A study was made of the structure of the intestinal cells, rectal glands, and anal muscles. Attention was called to the fact that there are two kinds of ejaculatory glands, one of which probably serves as a ‘cement gland,’ while the function of the other is still in doubt.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050490107
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  • 47
    Digitale Medien
    Digitale Medien
    An investigation of the nervous system as a possible factor in the regulation of ciliary activity of the lamellibranch gill (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 147-193 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Certain variations of ciliary activity in the lamellibranch gill occur which are an intrinsic part of the gill tissue and which are due to causes other than environmental changes. Experimental and morphological evidence indicates that the central nervous system is not involved in the production of these variations.A comparative study of laterofrontal and lateral ciliated cells leads to the conclusion that the coordination impulse passes through the cytoplasm of the cell and that the velocity of the propagation wave is influenced by the number of cell walls per unit length through which it passes. It is suggested that the ciliary rootlets in the laterfrontal cells, due to their arrangement bring the impulse simultaneously to both rows of cilia within a single cell.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510104
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  • 48
    Digitale Medien
    Digitale Medien
    The spermiogenesis of Succinea ovalis say, with special reference to the components of the sperm (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 243-289 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: An investigation of the spermiogenesis of Succinea ovalis Say, a small terrestrial pulmonate, has revealed: 1) The germ cells are differentiated from indifferent germinal epithelial cells. In this form the germinal epithelium is a true epithelium, and not a syncytium. 2) Forty chromosomes are found in the spermatogonial divisions and twenty in the maturation divisions. 3) Early in spermiogenesis the proximal centriole penetrates through the spermatid nucleus and, with the oxychromatin, forms an intranuclear rod similar to that reported for certain prosobranches. The homology and significance of the rod are discussed. 4) Of the cytoplasmic structures, the mitochondria and the Golgi apparatus were followed through all stages of spermatogenesis. 5) At the maturation divisions the mitochondria are grouped into peculiar. thread-like structures. Some of the mitochondria take part in the formation of the sheath around the axial filament of the spermatozoon, while the remainder are sloughed off with the cytoplasmic remnant. 6) The Golgi apparatus consists of a number of banana-shaped rods closely grouped around the idiosome. Three to five Golgi rods are found in the spermatid stages. A portion of the Golgi apparatus and idisome (acroblast) forms the acrosome, and the Golgi remnant is discarded at the end of spermatogenesis. 7) In mature sperm both head and tail have a spiral structure. The origin and nature of the spirals are pointed out.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510107
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  • 49
    Digitale Medien
    Digitale Medien
    Blood formation in the african lungfish, under normal conditions and under conditions of prolonged estivation and recoveryThis paper was awarded the Virginia Academy of Science research prize for 1930. (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 319-371 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The blood cells of the African lungfish, Protopterus ethiopicus, are very large and resemble those of urodeles. Leucocytes are especially plentiful and rich in variety, including eosinophils, special eosinophils, [meta-eosinophils] with atypical granules, monocytes, thrombocytes, lymphocytes, and basophils.The chief hemocytopoietic organs are the spleen, intestine, and kidneys. The lungfish spleen, embedded in the wall of the stomach, represents an intermediate phylogenetic stage between the disperse intra-enteral type of the hagfish and the compact extra-enteral type of other vertebrates.Erythrocytes are formed in the spleen pulp, granulocytes in the granulocytopoietic organ of the intestine and in the capsules of kidneys, gonads, and spleen. Thrombocytes and monocytes are differentiated in the spleen and general circulation. Basophils arise in the spleen and intestine. Lymphoid cells of all types arise in the spleen. Evidence is presented bearing upon the hemocytopoietic capacity of the various types. Cells with [Russell bodies] also occur in the spleen.In lungfishes subjected to long periods of dry estivation, erythrocytopoiesis practically ceases. Granulocytes, however, appear to play an important rǒle, possibly in fat metabolism. The large variety of meta-eosinophils, a unique feature of the lungfish, appears to be associated with the habit of estivation.Recovery from estivation may show numerous amitoses of erythrocytes in the general circulation. Other cells which divide in this manner are young thrombocytes, granulocytes, monocytes, and lymphoid hemoblasts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510203
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  • 50
    Digitale Medien
    Digitale Medien
    Notes on the postnuclear, acrosome-seat granules, and ‘vacuome’ in Desmognathus fusca spermatogenesis (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 597-612 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The acrosome in Desmognathus, Spelerpes, Plethodon, salamander, Amphiuma, etc., is attached to the nucleus in connection with an acrosome seat, which forms a shallow cup, traced back to a number of granules in the early spermatid. A postnuclear plate is present in the above-mentioned urodeles, and is derived from a small number of minute granules which assemble in the spermatid and become fixed onto the nuclear membrane. The centrosomes of the spermatid are visible intravitam. The ‘vacuome’ is formed of minute neutral-red-staining globules embedded in the idiozome. No connection appears to exist between mitochondria and Golgi bodies, as is postulated by the vacuome-chondriome hypothesis (Parat).
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510209
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  • 51
    Digitale Medien
    Digitale Medien
    Studies on the comparative histology of the digestive tube of certain teleost fishes II. A minnow (Campostoma anomalum)Studies from the Department of Zoölogy, The University of Nebraska, no. 168. (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 1-25 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This paper presents a study of the normal histology of the digestive tract of an herbivorous teleost, the minnow Campostoma anomalum (Raflnesque). The tunics of the buccal cavity, pharynx, esophagus, and intestine are described; particular attention is given to the mucosa because of the specializations occurring in that coat, such as taste buds, goblet cells, callous pad, etc. Because of the very decided anatomical and histological differences existing between the anterior and posterior regions of the pharynx, due to the presence of a callous pad and pharyngeal teeth, it has been deemed advisable to consider the pharynx as divisible into an anterior and a posterior region. Thyroid tissue was found in the submucosa of the anterior pharynx. No gastric epithelium was demonstrated, the ‘intestinal bulb,’ the only enlargement of the coelomic portion of the digestive tube, being lined with epithelium presenting only minor differences from that found in the coiled tubular intestine.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520102
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  • 52
    Digitale Medien
    Digitale Medien
    Variations in chromosome number in the spermatogenesis of Philosamia cynthia (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 45 (1928), S. 599-613 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A study of spermatogenesis was made on four groups of a pedigreed strain of the moth Philosamia cynthia, and the results were compared with spermatogenesis in the wild material.Deviations from the normal number of chromosomes were observed in two groups. In some individuals the haploid number was 12 instead of 13. Giant spermatocytes were also observed with twenty-four chromosomes. In other individuals, two haploid numbers, 13 and 14, occurred in the same testis.The twelve-chromosome condition is due to linkage of two chromosomes during the late prophase of the primary spermatocyte. The double chromosomes thus formed appeared to divide equally in both divisions. The origin of the fourteenth chromosome was not determined.Correlation of the genetic and cytological data indicates the restriction of aberrant chromosome complexes to two of the four groups and the regularity of the twelve-chromosome complex in certain families, suggesting the conclusion that a new strain arose in the pedigreed material with regard to chromosome variability and that the twelve-chromosome condition is a well-defined characteristic, partly established in some families and probably fully established in others.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050450209
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  • 53
    Digitale Medien
    Digitale Medien
    The chromosomes of the guinea-pigContribution no. 208 from the Department of Zoölogy, University of Texas. The writer has been aided in this work by grants from the Committee for Research on Sex Problems of the National Research Council. The work has been done under the direction of Prof. T. S. Painter. (1928)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 46 (1928), S. 131-141 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The spermatogenesis of five guinea-pigs was studied. The spermatogonial chromosome number is approximately sixty-two plus or minus two. The primary spermatocyte number is approximately thirty-one. The spermatogonial number in the early prophase is lower than it is in later stages. This condition is due to late fragmentation of the large chromosomes found in the earlier stage. A possible sex chromosome of the X-Y type may be identified. Its components segregate during the first maturation division.
    Zusätzliches Material: 24 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050460105
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  • 54
    Digitale Medien
    Digitale Medien
    Masthead (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530101
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  • 55
    Digitale Medien
    Digitale Medien
    The histology of posterior regeneration in the polychaete Chaetopterus variopedatusThe material for this work was collected at the Woods Hole Marine Biological Laboratory during August, 1929; the subsequent work was completed in the Zoölogical Department, University of Chicago, Illinois, and the Anatomy Department, University of California, Berkeley, California. The author wishes to thank Dr. F. R. Lillie for his assistance. (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 23-58 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: After amputation, the wound is closed by the protrusion and lateral expansion of the alimentary canal over the cut muscles and its final fusion with the epidermis laterally after about twenty-four hours. Associated with the expansion is a divergence of the two adjacent halves of the ventral nerve cord in the last remaining segment. As a result, the whole of the new regenerated lobe behind the ring of the cut epidermis is interneural; i.e., it is an enlargement of the normally small area separating the two nerve cords. Undifferentiated cells, or neuroblasts, are normally located interneurally, and during regeneration these neoblasts proliferate throughout the enlarged interneural zone of the papilla and migrate throughout the lobe. At first the neoblastic mesenchyme filling the lobe is loose and homogeneous, but as the cells settle down against the outer wall they replace the old intestinal cells and assume the characters of new epidermis. Internally, the mass acquires paired cavities, while the cells surrounding the cavities differentiate into muscle, peritoneum, etc. Thus one type of cell gives rise to the whole of the regenerated papilla. These cells are also the mother cells of the gametocytes.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530103
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  • 56
    Digitale Medien
    Digitale Medien
    Some cytoplasmic structures in the male reproductive cells of a pseudoscorpion (Chelanops corticis) (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 97-131 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The chondriosomes of the germinal epithelium are vesicular, whereas the Golgi material takes three forms. The aggregation of chondriosomes about the Golgi cap, located on the nucleus, suggests a chemical interchange between these in the growth period. They become cylindrical as the Golgi cap moves from the nucleus and becomes spherical. It is at this time joined by other Golgi material. The entire aggregation is dispersed previous to the maturation divisions, where the inclusions studied are only approximately equally divided, in contrast to conditions in the true scorpion, Centrurus exilicauda. Golgi granules on chondriosomal surfaces in the spermatid again suggest chemical interchange. The later changes of chondriosome vesicles to discs, and back to spheres, may be means of regulating chemical reaction. A close relation between chondriosomes and Golgi material is indicated by various bodies, of Golgi origin, within the former in the spermatid. A thick thread finally originates from among the chondriosomes of the elongated sperm. Spiral threads surrounding the elongating nucleus arise from reunited Golgi material, a derivative of this substance not previously recorded. The acrosome, also of Golgi origin, undergoes several changes in shape and shows several parts. The elongated nucleus, spiral thread of Golgi origin, acrosome, chondriosomal thread, and unusually long axial filament become coiled and encysted in an oval mature sperm capsule. In the female duct the sperm uncoils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530105
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  • 57
    Digitale Medien
    Digitale Medien
    Coordination of ciliary movement. II. The effect of temperature upon the ciliary wave lengthThe investigation has been made possible through funds granted by the Chemical Foundation and the National Research Council. (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 265-276 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ciliary wave length is a constant in the temperature range of 10° to 30°C. and in Modiolus demissus has the average value of 13.1 μ. Comparison of these data for ciliary coordination with those of nerve conduction probably indicates that the two physiological processes possess certain properties in common. The cells which bear the cilia are 12.75 μ long and the variation in ciliary wave length and cell length is about the same, which may indicate a possible cytophysiological relationship between the two.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530204
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  • 58
    Digitale Medien
    Digitale Medien
    Keimbahn determinants and continuity of the germ cells in Sphaerium striatinum (Lam.) (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 345-365 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: During oogenesis granular mitochondria become concentrated in the proximal portion of the oocyte and remain concentrated in the line of cells that gives rise to the germ cells. Two cells of characteristic structure, appearing at gastrulation one on either side in the mesoderm, contain this mitochondrial cloud. All functional germ cells seem to be lineal descendants of these two primordial germ cells. The cloud disappears during gonad formation, but reappears in oocytes of the next generation. Except during meiosis and fertilization the germ-cell cycle is traceable from fertilized egg to sexual maturity. Details of meiosis and chromosome number were not ascertained.Capacity for producing germ cells in Sphaerium is traceable from a definite region in the egg to primordial germ cells through a localized cloud of mitochondria in the mature ovum and certain cells of cleavage stages. Mitochondria, therefore, serve as a Keimbahn determinant in the sense that they mark a region of oocyte cytoplasm destined for cytoplasm of primordial germ cells. They are not considered causal factors in production of germ cells, but are probably storage products persisting unused in the egg and in cleavage cells having lower metabolic rates. Disappearance of these mitochondria during gonad formation is explained by their dispersal among a number of cells and by their utilization in furnishing energy and material for production of new cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530207
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  • 59
    Digitale Medien
    Digitale Medien
    Masthead (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530301
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  • 60
    Digitale Medien
    Digitale Medien
    Polyploidy and metaphase patterns (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 443-471 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A cyst of tetraploid first spermatocyte metaphases is described in the coreid hemipter Archimerus alternatus (Say), all other divisions in the testis being of normal diploid constitution. The striking fact is that in spite of the doubling of their number the chromosomes closely follow the group pattern characteristic of the corresponding normal divisions. In the latter the first metaphase always shows a ring of six autosome bivalents with a single m-chromosome bivalent at its center and a single univalent X-chromosome lying outside the ring (as in coreids generally). In corresponding tetraploids the numbers are respectively 12, 2, and 2. Three additional interesting features of the tetraploids are: 1) the fact that the two m-bivalents are always lined up end to end to form an axial quadrivalent chain; 2) that although two X-chromosomes are present (as in the normal female), they are never united to form a bivalent as in that sex; and, 3) that in the prophases (of which a few are present in the cyst), at least one pycnotic X, or chromosome nucleolus, is present.A critical discussion is offered of the general problem of the mechanism of chromosome movements and groupings, together with a review of recent literature. The conclusion is urged that the chromosomes themselves play an active and important part in these processes, and the possible genetic relations between chromosomes and spindle substance are discussed.
    Zusätzliches Material: 24 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530302
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  • 61
    Digitale Medien
    Digitale Medien
    The distribution of the branchial nerve in Mytilus edulis and its relation to the problem of nervous control of ciliary activity (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 195-205 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The branchial nerve of Mytilus edulis, traced by means of serial sections, has been found to be limited entirely to the epithelial and connective tissues bordering the axis of the gills. Most of the numerous branches which originate from the branchial nerve extend posteriorly and lie close to the interfibrillar matrix of the connective tissue which supports the epithelium of this region. Fibers of these nerves have been traced to this epithelium.The chitinous supporting structures of the gills lie in close proximity to these nerves, yet neither nerves nor nerve fibers have been observed to penetrate them. Moreover, a careful study of the gill tissues fails to reveal the presence of structures which might be interpreted as nerves or nerve fibers.Since no innervation of the gills has been demonstrated, it seems probable that the ciliary activity of the gill epithelium is not regulated by means of fibers connected with the central nervous system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510105
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  • 62
    Digitale Medien
    Digitale Medien
    The morphology of Spironympha, with a description of a new species from reticulitermes hesperus Banks (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 291-307 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Spironympha is discussed as valid genus. It was described by Koidzumi ('16); later it was redescribed by the same author as Microspironympha ('21). Therefore, according to the rules of nomenclature, it is Spironympha.The genus is compared with the related genera: Spirotrichonympha, Holomastigotes, and Microjoenia.Spironympha is characterized by four flagellar bands which are spirally wound around the anterior part of the body; these bands occur only in the anterior end, whereas in Spirotrichonympha they extend almost to the posterior end. The parabasals are few in number, and they are attached to the basal granules of the flagellar bands; the anterior end is clear and almost free from cytoplasmic granules; and there are twenty to thirty anterior flagella which are attached to the base of the centroblepharoplast or to the basal granules of the flagellar bands. An axostyle is present.No centrosome occurs within the nucleus, but the centroblepharoplast has this kinetic function.Spironympha ovalis is described as a new species. It is ovoid; the average size is 38 μ to 44 μ. An axostyle is present. The host is Reticulitermes hesperus Banks.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510108
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  • 63
    Digitale Medien
    Digitale Medien
    Recovery from immersion in water. An index of metabolism and the condition of the gonads in Drosophila melanogaster Meigen and Popillia japonica Newm. (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 435-465 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In some insects the selection of individuals which recover in equal periods of time from immersion in water may be used to obtain material of approximately uniform physiological state; Drosophila melanogaster, Meigen, was found to have a mean of recovery for the males 0.97 ± 0.542 minute later than the females, which would indicate a lower metabolic rate for the males. The Japanese beetle, Popillia japonica Newm., was found to have a mean of recovery from immersion in water of both sexes the same in August, while in September the males were retarded by 8.1 as compared with females. This would indicate that the males have and equal me abolic rate in August with the females and a lower rate in September. Carbon dioxide, hydrogen, and nitrogen produce in the flies a condition of asphyxiation similar to immersion in water. [Vestigial] flies recover from immersion in water in a fashion similar to ‘wild’ flies.The recovery periods from immersion in water in the flies can be used to group individuals into those possessing approximately equal egg-laying capacities and to isolate spent individuals from others still capable of laying eggs. Yeast appears to be more of a stimulant to egg laying than it is to larval growth. Groups of flies which were fed yeast were found to average 71 per cent increase in egg laying over groups of flies that were not fed yeast. The O2 consumption of the groups of flies actively laying eggs, as contrasted with the groups which were not so active, was found in the former to be 32.9 per cent greater.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050510205
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  • 64
    Digitale Medien
    Digitale Medien
    Masthead (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520101
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  • 65
    Digitale Medien
    Digitale Medien
    A study of living sperm cells of certain grasshoppers by means of the ultraviolet microscope (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 91-113 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This paper discusses very briefly the ultraviolet microscope and the developments which have led to a successful technique for optically sectioning living cells; also the ultraviolet photomicrographs of living sperm cells of certain grasshoppers, which show clearly the spinning out of the chromonema from solid blocks of the diatene stage, the pairing of same in the leptotene stage, the development of the tetrads, the final distribution of the chromosomes in the resulting spermatids and their return to a spiral chromonema, each inclosed in its own vesicle. The details of the cytoplasm are equally well brought out.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520105
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  • 66
    Digitale Medien
    Digitale Medien
    Thermal relationships in the neutral-red reaction (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 165-194 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Neutral-red staining in Daphnia, legume seeds, starfish eggs, and Palaemonetes shows reactions to temperature changes which may be correlated with the thermal reactions of enzymes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520108
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  • 67
    Digitale Medien
    Digitale Medien
    The parietal fossa and related structures in the plagiostome fishes (1929)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 543-561 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The parietal fossa or pit is situated in the middorsal line between the ear capsules. From its floor four (sometimes only two) apertures lead into the ear capsules. The anterior apertures are the foramina of the endolymphatic ducts; the posterior ones are the fenestrae. Through the fossa each endolymphatic duct passes from its formen to its external aperture in the dorsal integument, describing in its course a loop with the convexity directed anteriorly. The part of the duct involving the loop is enlarged into an endolymphatic pouch. Into the angle of this loop a small muscle is inserted which is a continuation of the anterior trunk muscles, or one taking a more lateral origin from the edge of the fossa. The fenestra may or may not be closed by a definite fenestral membrane. The posterior semicircular canal (posterior utriculus) bears a peculiar relation to the fenestra. The endolymphatic pouch, like the sacculus, contains otoconia, and sometimes siliceous sand grains. Various functions have been assigned to the endolymphatic organ. There is no convincing experimental evidence as to its significance.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050480210
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  • 68
    Digitale Medien
    Digitale Medien
    The ontogenetic history of the mitochondria of the hepatic cell of the white rat (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 485-511 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This work was designed to determine the ontogenetic variability of the morphology of mitochondria of the hepatic cell.The mitochondria of the cells of the hepatic diverticulum are minute spheres. These spheres enlarge, become associated, forming beaded filaments, which in turn become smooth filaments, the process culminating in the twenty-day fetus. There is no individual or lobular variabillty in fetuses of a given length. One-half day before birth the above process is reversed, so that separate spheres are found in the eight- to twelve-hour young. This enlargement and enspherulation are accompanied by an accumulation of large quantities of glycogen. After this age, the spheres become associated into beaded filaments again and the glycogen disappears, the cycle ending at thirty-three hours. From two to eight days of age there is great individual variability.Mitochondrial morphology characterstic of the adult is first found in the fourteen-day young, when cells contain long, smooth or beaded filaments, rods, and spheres. There is no lobular variation as to types of mitochondria, but only in numbers, the cells around the central vein containing fewer mitochondria than other cells of the lobule. Variation between individuals after birth is due to something other than age, type of food, period of digestion, and length of starvation. Fat is formed within spherical chondriosomes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520206
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  • 69
    Digitale Medien
    Digitale Medien
    Chromosomes of three species of mantidae (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 525-533 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: There are twenty-seven spermatogonial chromosomes in Tenoder'a sinensis, three of which are larger than the others and lag behind in anaphase. These three chromosomes have been traced through the prophases of the first spermatocyte to the metaphase, where they appear as a hexad. In the first spermatocyte division two of the constituent diads of the hexad pass to one pole, the remaining one to the other, thus giving rise to two types of second spermatocytes, one with thirteen and the other with fourteen chromosomes. There are twenty-eight chromosomes in somatic metaphases of the female; four of these chromosomes are larger than the others. The sex chromosomes of the male are represented by the formula Xa + Y + Xb, that of the female by 2Xa + 2Xb.Similar conditions are reported for Mantis religiosa and Stagmomantis carolina.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520208
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  • 70
    Digitale Medien
    Digitale Medien
    Developmental stages of the chondrocranium in some selachians (1931)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 565-592 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Serial sections of seven embryos were examined, in four of which the chondrocrania were reconstructed. Parachordals appear as independent precartilages on each side of the notochord in the otic region. Later chondrification occurs, and they fuse with the notochord. Orbitals and trabeculae appear as independent precartilages; later, as cartilages they fuse with the basal plate and with each other, forming the cranial wall between the orbital cavity and brain. An apparent shifting posteriorly of the bases of the fifth, seventh, and eighth cranial nerves, in respect to the anterior end of the notochord and to the otic vesicles, occurs between the 10-mm. and the 60-mm. stages. The otic vesicles, proportionately small in the 10-mm. stage, reach their relatively largest size in the 19-mm. embryo. The floors of the otic capsules begin as lateral extensions of the basal plate at the 25-mm. stage, and from these anlagen chondrifications extend, forming the anterior and posuerior cupolas. Most of the tegmen cranii forms by chondrifications that approach the median plane from each side. It is practically complete in the 60-mm. embryo. The cervical neural arches also contribute in forming the tegmen cranii and the occipital region. The ventrally recurved end of the notochord of the 10-mm. stage persists through the 60-mm. embryo.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050520210
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  • 71
    Digitale Medien
    Digitale Medien
    The early develoment of the duck's egg, with special reference to the origin of the primitive streak (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 133-187 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study deals with the development of the duck embryo from the unincubated blastoderm to the 1-to-3-somite stage. In the unincubated stage the thickened posterior germ wall is the most active region mitotically, contributing cells to complete the entodermal layer. The slightly thickened ectoderm of the posterior half of the pellucid area is the precursor of the embryonic shield. During incubation this ectoderm increases in height, forming the embryonic shield. The primitive streak arises in the posterior part of the shield, where tall ectodermal cells in the midline become several-layered and proliferate cells from their ventral surface which migrate laterally, becoming mesoderm. At first short and broad, the streak becomes longer and narrower until it attains its definitive stage.The greatest proliferation of ectodermal cells occurs always at the anterior end of the streak of all stages, forming at the definitive stage a definite thickening-Hensen's node. Proliferation diminishes posteriorly along the streak.The number and orientation of mitotic figures indicate cell movements as follows: Prestreak stages-ectodermal cells migrate from posterior part of shield toward midline, thence forward in midline; early streak stages-anterior movement in streak and to sides of streak, and lateromedial movement from sides toward middle of streak; definitive streak stages-postero-anterior and lateromedial migration of cells.The embryonic axis, of prestreak and streak stages, lies approximately at right angles to the egg axis in slightly over 50 per cent of the cases.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530106
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  • 72
    Digitale Medien
    Digitale Medien
    The architecture of the parietal cells of the salivary glands of the grasshopper, with special reference to the intracellular canaliculi, Golgi bodies, and mitochondria (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 223-241 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The parietal cells of the salivary glands of the grasshopper are large and roughly spherical or sometimes pyramidal in form, scattered for the most part singly among the zymogenic cells of the lobules. They possess a magnificent system of intracellular canaliculi into which their secretions are directly emptied and conveyed to the exterior of the cell. These intracellular canaliculi are strikingly impregnated with osmic-acid methods (Nassonov, Mann-Kopsch) in a manner comparable to the contractile vacuole of Paramecium as described by Nassonov. However, in addition to the impregnated system of intracellular canaliculi, Golgi bodies are found evenly distributed throughout the cell in the form of crescents, semicircles, or ring-like structures typical of insect tissue.Inasmuch as a direct homology between the intracellular canaliculi and the contractile vacuole of Paramecium, both from the point of view of morphology and physiology, seems justified, we question the inference drawn by Nassonov that the impregnated walls of the contractile vacuole in Paramecium actually represent Golgi material. Deduction is made from these and previous studies that the magnificent network of ‘vacuome-Golgi apparatus’ described by Parat and Painlevé ('24) in the salivary glands of Chironomus larvae is nothing more or less than intracellular secretory canaliculi.Mitochondria in the parietal cells are abundant in the characteristic form of short rods and filaments. No evidence of a direct transformation of mitochondria into Golgi bodies. as held by Parat, was observed. Golgi bodies and mitochondria show no marked topographical relationship to the intracellular secretory canaliculi.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530202
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  • 73
    Digitale Medien
    Digitale Medien
    The chondrocranium of a 23-mm. necturusContribution from the Zoölogical Laboratories, University of Illinois, no. 424. (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 327-343 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study is based on a wax model reconstructed from serial sections stained with basic fuchsin and picro-indigo-carmine. It shows: 1) that the columna ethmoidalis and planum basale are chondrified at this stage; 2) that a cartilaginous antorbital process is present; 3) that the stapedial plate is cut out from the wall of the otic capsule; 4) that the so-called crista trabecularis is an independent element homologous with the sphenolateralis of the Anura; 5) that the fourth visceral arch is not present and that the fifth is still in the precartilaginous stage; and, 7) that there is no evidence that a pro-occipital vertebra is formed.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530206
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  • 74
    Digitale Medien
    Digitale Medien
    The structure of opalinids, as revealed by the technique of micro-incinerationAided by an appropriation from a grant made by the Rockefeller Foundation to Washington University for research in science. (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 381-388 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Opalinids from the rectum of Rana pipiens were isolated in large numbers and fixed in a mixture of nine parts of absolute alcohol and one part of neutral formalin. These were embedded in paraffin and incinerated according to the technique of Policard. Examination of the preparations by dark-field illumination showed that the micro-incinerated protozoa retained their distinctive morphological and cytological characters, for the mineral ash had the same topographical distribution as the cell inclusions in the control stained preparations.The coarse vegetative granules of the cytoplasm were preserved as distinct masses of ash which corresponded exactly to these bodies in the control preparations. The structure of the myonemata and the cilia was perfectly preserved. The chromatin material of the nucleus, more or less abundant, left little or no ash, which is quite in contrast to the findings of Scott with regard to amphibian and mammalian nuclei.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530209
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  • 75
    Digitale Medien
    Digitale Medien
    DIE BILDUNG DER ERYTHROCYTEN IM KERNE DER PLASMOCYTEN; DER HÄMOGLOBINSCHWUND IM BLUTKREISLAUFE MIT DER PIGMENTMETAMORPHOSE UND OHNE DERSELBEN UND DIE BESONDERE ELIMINIERUNGSART DER CHROMATINSUBSTANZ AUS DER ZELLE IM BLUTE DES BATRACHOSEPS ATTENUATUS ESCH. (1932)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 53 (1932), S. 593-603 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In the blood of Batrachoseps one part of the erythrocytes is formed inside the nucleus of plasmocytes as a result of the metamorphosis of chromatin substance. When erythrocytes are completely formed, they separate themselves from the plasmocytes.Disappearance of the hemoglobin of erythrocytes with pigment metamorphosis is visible in the drawings.When the disappearance of hemoglobin with pigment metamorphosis takes place, the color of the hemoglobin cytoplasm frequently becomes very pale. The hemoglobin cytoplasm may vanish also without pigment metamorphosis in such a way that the whole cell (nucleus and cytoplasm) swells, and the cytoplasm becomes paler, and finally only a pale shadow remains which is rather difficult to distinguish. The author has noticed in the blood of Batrachoseps, besides extrusion of small nuclei from the erythrocytes, also a particular way in which chromatin substance is eliminated from the cell. While the cell and the nucleus become pear-shaped, the nucleus moves toward the periphery, touching the surface of the cell with its funnel-shaped narrow side. From this narrow side the chromatin substance flows out in the form of a band stained red, according to Romanowsky.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050530306
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  • 76
    Digitale Medien
    Digitale Medien
    Masthead (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050550301
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  • 77
    Digitale Medien
    Digitale Medien
    Localization of mineral ash in the organelles and cytoplasmic components of paramecium (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 421-433 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Paramecium caudatum was studied by micro-incineration, by stained control sections, by vital staining, and by osmic impregnation. It was found that a slow initial heating and a slow cooling after incineration greatly reduce the amount of distortion and shrinkage in the incinerated specimens. Most of the cytoplasmic components and organelles, including vacuome, chondriome, cilia, and basal granules, trichocysts, food vacuoles, and the nuclei, could be identified by their ash. No ash is found in the pellicle and only a small amount in the hyaloplasm. None of the osmiophilic components such as granules or the walls of the contractile vacuole could be identified in the incinerated specimens with certainty. The larger amount of ash in the endoplasm as compared with the ectoplasm is due to the large number of granules in the former region. The nucleus and some of the granules near the nucleus show traces of iron.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050550302
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  • 78
    Digitale Medien
    Digitale Medien
    Studies upon regeneration. I. The constrasting powers of regeneration in planaria and procotylaSupported by a grant from the Committee on Radiation, National Research Council. Acknowledgments are also due to Keio University, Tokyo, Japan, for assistance given the senior author during his service as visiting professor, 1932-1933. The present paper is introductory to studies of the effects of radiation upon the normal structures and activities here described. A number of individuals have assisted in varying degrees in these investigations. Since work present paper, her name appears as a joint author. Certain work by6 C. D. Turner was similarly helpful. The senior author, who has thus supplemented his own studies of the material, has written the paper and assumes responsibility for the observations and their interpretation. (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 477-513 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: When sexually mature Procotyla fluviatilis Leidy (commonly but erroneously known as Dendrocoelum lacteum) are cut transversely into head, pharyngeal, and tail pieces of about equal length, the head and pharyngeal pieces fail to regenerate in a large percentage of cases and tail pieces never regenerate. When regeneration occurs in head and pharyngeal pieces it is somewhat slower than in similar pieces of Planaria maculata Leidy and Planaria agilis Stringer with which comparisons were made. Cutting mature Procotyla into larger numbers of pieces usually results in death of all, although smaller pieces from prepharyngeal regions sometimes regenerate. Juvenile P. fluviatilis have greater powers of regeneration, as shown by cutting head and pharyngeal regions into greater numbers of pieces, but tail pieces do not regenerate. These observations confirm and extend those of earlier investigators. Such a restricted power of regeneration contrasts with well-known powers in P. maculata and P. agilis. Counts of formative cells, from which new parts arise in all three species and which are regarded by the authors as a persistent embryonic stock, indicate about 8.5 such cells in P. maculata to 1 in P. fluviatilis per unit area. It is concluded that regeneration in planarians is correlated with numbers of such formative cells and that histological factors are no less important than physiological ones. The paper is preliminary to a study of effects of x-rays upon regeneration.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050550304
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  • 79
    Digitale Medien
    Digitale Medien
    The development of the ovary in the grasshopper, Melanoplus differentialis (acrididae; orthoptera)The author is indebted to the National Research Council for a Fellowship during the year 1929-1930 during which the work herein described was partially completed; also, to the Marine Biological Laboratory, Woods Hole, Massachusetts, for facilities for work during the summer of 1930. (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 515-543 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Each indifferent genital rudiment in the grasshopper embryo is composed of the following: (1) a terminal filament membrane; (2) an epithelial plate of indifferent cells, the dorsal cell mass; (3) the central cell mass containing germ and indifferent cells; (4) the ventral cell strand, and, (5) a delicate, investing membrane, the outer limiting membrane. It is roughly spindle-shaped in transverse section and extends from the first to the eighth abdominal segments.In the sexual differentiation of the genital rudiment the dorsal cell mass is retained as a definite embryonic rudiment in the female, but becomes an indistinguishable part of the central cell mass in the male.Ovarian development is initiated in the dorsal cell mass area, where cell aggregations are formed. Each aggregation is ultimately surrounded by the ingrowing outer limiting membrane to form distinct cellular columns. A latero-ventrad extension of this ingrowing process into the central cell mass continues the column formation process into the latter and results in the formation of a distally tapering structure composed of indifferent cells distad and germ cells and indifferent cells proximad. This structure constitutes the rudimentary ovariole which finally differentiates to form the terminal filament, germarium, and vitellarium.The ovarian portion of the oviduct and the tubular connection between the ovariole and oviduct are differentiated from the ventral cell strand.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050550305
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  • 80
    Digitale Medien
    Digitale Medien
    The mesodermal relations of the pars buccalis of the hypophysis in the duck (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 611-631 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This paper describes the cellular relations between the prechordal mesoderm and the hypophyseal analage in duck embryos from the first to the eighth day of incubation.At nineteen somites the ectoderm destined to form hypophysis is seen as a plate of cells lying under the mesodermal mass anterior to the notochord. It extends anteriorly in intimate contact with the base of the forebrain, and posteriorly for about the same distance to the oral membrane. Following the lateral growth of the prechordal mesoderm and the rapid overgrowth of the forebrain, Rathke's pouch is definitely outlined. The upward expansion of the pouch, concomitant with the lagging of some of the prechordal mesoderm in the midline, effects a very close relation between these cells and those at the tip of the pouch. With the lateral expansion of the premandibular head cavities, some of the mesoderm adheres to walls of Rathke's pouch in the form of rods or knobs. As development proceeds the inherent growth tendencies of ectoderm and mesoderm express themselves differently and the rods or knobs become constricted off from the pouch, forming in its vicinity vesicles which exhibit a definite lumen.The question of an entodermal contribution to the hypophysis in this form is briefly considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050550309
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  • 81
    Digitale Medien
    Digitale Medien
    The distribution of chitin in an insect (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 51-58 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: By treating the clean skeletal tissue of an insect with concentrated KOH at 160° C., the contained chitin is converted to chitosan, and all pigmentation and admixtures are removed. The per cent distribution of chitin, expressed as chitosan, in the exoskeleton of the cockroach, Periplaneta fuliginosa, ranges from 37.65 in the dorsal abdomen to 18.22 in the hindwings. Other regions contain the following per cents: ventral abdomen, 37.11; metathoracic legs, 35.55; mesothoracic legs, 33.28; prothoracic legs, 32.24; pronotum, 31.55; head, 31.07; genitalia, 29.28; dorsal thorax, 29.07; ventral thorax, 28.33; antennae, 27.77; cerci, 25.65; and forewings, 19.99. Regional variations are constant in different individuals of the same species. The crop and gizzard contain 18.69 per cent; the hindgut, 18.15 per cent. The remainder of the alimentary tract contains no chitin. Traces of chitin are found in the trachea. No chitin is found in the egg-cases of this species. No correlation between chitin content and pigmentation or hardness is shown. Based on results from three trials, using thirty insects, the per cent of chitosan in the clean, dry chitinous material from the entire animal is 29.60; the per cent of chitosan based on the weight of the live animal averages 2.01.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560104
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  • 82
    Digitale Medien
    Digitale Medien
    Somatic mitoses of Drosophila melanogaster (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 125-155 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The chromosomes of D. melanogaster have been followed through the entire cycle of mitosis in ganglion cells. Primary constrictions exist at about the middle of the second and third chromosomes, at a sub-median position in the Y, at a sub-terminal in the X, and probably also at a sub-terminal position in the fourth chromosome. Secondary constrictions, in addition to those reported by Bridges, are sub-terminal in the arms of the second and third chromosomes. A pronounced sub-median secondary constriction in the left limb of the second chromosome offers a criterion for distinguishing between the second and third chromosomes, and between right and left arms of the second chromosome. The proximal secondary constriction in the X-chromosome and that in the short arm of the Y are associated with the normal development of the nucleolus. Anaphase chromosomes are longitudinally double, the split following the turns of the chromonemata. Metaphase and anaphase chromosomes are essentially isodiametric from end to end, except at the constrictions or indentures. Somatic pairing of chromosomes reaches its maximum expression during late prophases, both in male and female ganglion cells. The four chromatids of the tightly appressed homologues open out in two planes giving distinct chiasma-like configurations. Separation of the paired chromosomes is completed in late prophase, so that at metaphase the homologous chromosomes are not in contact.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560107
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  • 83
    Digitale Medien
    Digitale Medien
    The cytology of the corpora lutea of the eweA thesis submitted from the Department of Zoölogy for the degree of Doctor of Philosophy at the University of Missouri. (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 181-202 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cytology of corpora lutea of non-pregnant ewes is described with reference to the origin, structure, fate, and function of these organs. The lutein cells, characteristic of corpora lutea, are derived from the cells of the stratum granulosum of the Graafian follicle; connective-tissue cells, embryonic cells, and non-striated muscle cells, from the theca interna; and erythrocytes, leucocytes, and histiocytes, from the blood stream. The lutein cells undergo changes in size, nuclear structure, and cytoplasmic inclusions correlated with the period in the estrous cycle and disappear during retrogression. Although secretory products have not been identified, a secretory function is postulated on the basis of the structure of the cell.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560109
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  • 84
    Digitale Medien
    Digitale Medien
    Localization of mineral ash in the organelles of trichonympha, a hypermastigote flagellate from zootermopsis angusticollis (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 231-241 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The three species of Trichonympha found in Zootermopsis angusticollis were studied by micro-incineration, by control sections, and by Macallum's methods for iron and calcium. The mineral ash is concentrated in the neuromotor system, chromatin, nuclear membrane, the posterior end where ingestion takes place, and in cytoplasmic granules. Micro-incineration and Macallum's Prussian blue method reveal iron in the chromatin alone; Macallum's haematoxylin gives a positive test for iron in the chromatin, rostrum, neuromotor fibrils, etc. It probably is not as specific as the other methods. The two staining methods give negative tests for iron except after acid hydrolysis. Calcium is present in the chromatin, neuromotor system, posterior region of the body, and in many endoplasmic granules. The localization of calcium is correlated with the localization of normally gelated regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560203
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  • 85
    Digitale Medien
    Digitale Medien
    A cytological study on the liver of the rat, with special reference to the ‘intracellular blood canaliculi,’ inter- and intracellular bile canaliculi, mitochondria and Golgi apparatus (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 407-421 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In sections from livers injected through the vascular system with Carter's carminegelatin or Berlin-blue gelatin masses at known, constant pressures, many cells were observed to contain ovoid or spherical bodies of the colored injection masses, similar to those described by Schäfer and his students, Herring and Simpson, as intracellular blood canaliculi.' In these livers practically all the cells were vacuolated. However, with livers injected with Berlin-blue gelatin mass dissolved in Locke's solution instead of distilled water, there were no intracellular masses and the cells appeared normal, though the sinusoids were completely filled with injection mass. The so-called ‘intracellular blood canaliculi’ described by Schäfer are interpreted as artefacts produced by a combination of factors, the most important of which is the difference in osmotic pressure. This is produced by the hypotonicity of the injection masses that are usually used, augmented perhaps by the effect of mechanical pressure used in administering the injection mass.Following impregnation of liver tissue by Golgi's rapid method, the usual network of intercellular bile canaliculi was revealed, but the presence of a permanent system of intracellular canaliculi was not observed. A few short, knobbed intracellular projections from the intercellular bile canaliculi were noticed; these probably represent the passage of secretion material into the intercellular bile canaliculi at the moment of excretion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560211
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  • 86
    Digitale Medien
    Digitale Medien
    Early development in some sciuridaeContribution no. 234 from the Zoölogical Laboratory of Indiana University. Submitted in partial fulfillment of the requirements for the degree, Doctor of Philosophy, in the Department of Zoölogy in the Graduate School of Indiana University. (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 477-511 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The early developmental history of Sciuridae (squirrel family), from the ovarian egg to the establishment of the germ layers, was studied in fixed material comprising ova and embryos from six species of five genera. No significant differences were noted in the major processes of development in the six species. Continuous diminution in the size of the ova occurs from the beginning of follicular vesiculation up to the early blastocyst stages. Corpora haemorrhagica are present in most of the recently ruptured follicles of all the species.Cleavage is regular, though adequal, up to the eight-cell stage, the blastomeres clustering into a compact mass. There is desquamation of cellular material from the periphery of the ovum between morula and blastocyst stages. At the same time cells within the blastocyst degenerate to add to the cavity originally formed by confluence of intercellular spaces. The cavity forms among the inner cells, an inner cell mass being left at one pole and an anti-embryonic mass at the other. The anti-embryonic cells produce much of the yolk-sac entoderm and contribute to the implantation mass. The latter mass forms a temporary attachment of the blastocyst to the uterine mucosa in these species. The definitive entoderm arises by migration and delamination of certain of the inner cell mass cells. A transitory notochordal canal, passing in a vertical plane through Hensen's node, is strongly suggested.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560304
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  • 87
    Digitale Medien
    Digitale Medien
    On the arterial system of the common Indian rat-snake, Ptyas mucosus (Linn.) (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 533-575 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The arterial system of Ptyas mucosus (Linn.) reveals the following interesting features: (1) A prominent diverticulum given off from the inner antero-dorsal edge of the left auricle. (2) Ridge-like continuation of the median hanging valve of the sinus venosus lining the ventral edge of the opening of the right precaval vein. (3) Guarding of the opening of the pulmonary vein by a portion of the inter-auricular septum abutting against it. (4) Presence of two longitudinal trunks on either side of the hepatic portal vein formed by the hepatic branches of the hepato-oesophageal arteries, which, uniting with one another, form a peculiar arrangement looking almost like a looped chain. (5) A complete arterial circuit in the female formed by the combination of the genital, supra-renal, and the anterior-most renal arteries of either side. (6) Chain-like arrangement formed by the alternate bifurcation and union of the posterior-most part of the longitudinal fat-body artery and also by its lateral branches, which unite with it here and there after giving off twigs to the fat bodies. (7) A pair of small arteries (or in some cases only one) called ‘arteria complexa’ which take their origin from the dorsal aorta opposite the openings of the iliac veins into the afferent renals.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560306
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  • 88
    Digitale Medien
    Digitale Medien
    The idiochromosomes of an earwig, Labidura riparia (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 361-369 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The diploid number of chromosomes of a species of Indian earwigs, Labidura riparia, is fourteen; six pairs of autosomes with X and Y idiochromosomes for the male; six pairs of autosomes with X and X for the female.The chromosome distribution is normal, and constant for all the individuals studied.X and Y are derived from a single chromatin nucleolus of the early growth period which assumes a clavate form later, and remains in the same form till the metaphase of the primary spermatocyte is reached.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560209
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  • 89
    Digitale Medien
    Digitale Medien
    Masthead (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560301
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  • 90
    Digitale Medien
    Digitale Medien
    A study of the chromosomes of Xiphophorus, Platypoecilus and of Xiphophorus-Platypoecilus hybrids during spermatogenesisThe writer wishes to acknowledge his indebtedness to Dr. C. L. Turner for advice and assistance. (1934)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 423-443 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: During spermatogonial stages in Xiphophorus and Platypoecilus maculatus and Platypoecilus couchiana and in the hybrid, two distinct types of cells are observed, a large lightly staining primary spermatogonium and a smaller deeply staining secondary spermatogonium. Chromosomes of primary spermatogonia of Platypoecilus maculatus and Platypoecilus couchiana differ somewhat from those of Xiphophorus helleri and Xiphophorus jalapa, but are very similar to those of the hybrid at this stage.Chromosomes of Xiphophorus at this stage are long and thin, while those of Platypoecilus and of the hybrid are somewhat short and thick. Visible chromosome differences appear only during the primary spermatogonial stages.The haploid group of chromosomes, numbering twenty-four in the hybrid, so resembles that of Xiphophorus and of these two species of Platypoecilus in both number and morphological characteristics during the primary spermatocyte division as to be practically indistinguishable from either. Persistent lagging of one large chromosome as it comes upon the equatorial plate during the primary spermatocyte division is very noticeable. Precocious division of this chromosome and the advancing of its two daughter components to the poles of the spindle in advance of other chromosomes indicates that this chromosome may be a sex chromosome. The fact that two daughter components are identical morphologically and that each secondary spermatocyte receives one of them suggests that the male in Xiphophorus and in Platypoecilus is homogametic.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050560302
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  • 91
    Digitale Medien
    Digitale Medien
    A study of the gastric glands of alligator mississippiensis (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 40 (1925), S. 169-189 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A review of the literature of the gastric glands of reptiles shows marked differences of opinion concerning the nature and character of the cells composing the gastric glands.The present investigation of the gastric glands of the alligator has been carried out by histochemical and physiological experiments, rather than by the usual morphological methods, but the results can be stated both in terms of structure and function.1The surface epithelial cells and those lining the gland pits in the fundic, cardiac, and pyloric regions of the stomach of the alligator are not strictly comparable functionally to the mucous cells of mammals.2The cells composing the necks and bodies of the glands in the fundus, according to histochemical reactions, are parietal cells.3Certain cells lying beneath the columnar epithelial cells lining the lumen of the stomach and the foveolae react to one method of fixation and staining as do the chief cells of mammalian material.4The results of the experiment with the vital dye, neutral red, show that the cells of the gastric pits, the necks and bodies of the glands in the fundus of the alligator's stomach, react identically as those of the mammalian stomach.5The gastric juice of the alligator is acid to litmus-paper and contains a free mineral acid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050400104
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  • 92
    Digitale Medien
    Digitale Medien
    A mechanism for the coordination and regulation of ciliary movement as revealed by microdissection and cytological studies of ciliated cells of mollusksThe senior author desires to state that the actual work involved in the collection, preparation, and study of the material on which this paper is based has been done by Mr. Schmitt during his senior year at Washington University. The work carried credit toward the A.B. degree. The authors were associated during the investigation, in the relation of teacher and pupil. (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 40 (1925), S. 479-515 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Systems of fiber-like structures traverse ciliated cells and epithelia in a way to suggest conduction paths for stimuli for coordinating and regulating ciliary movement, and results of microdissection support such an interpretation.Some fibers of the systems in epithelia of the gill terminate on the nuclear membrane, some between nuclei in the basal cytoplasm.The observed double refringency of the fibrillar apparatus places it in the category of irritable and contractile substance.Bipolar cells and nerve-like fibers lie immediately below and parallel with ciliated epithelia of the gill, but direct connections of these fibers with the intracellular system, although suspected, was not demonstrated.Ciliated epithelia of the gill are syncytial in character in the direction of the beat of cilia.Interciliary structures occur in the cuticular portion of ciliated epithelia which are interpreted to function in taking up strains in the gelled cytoplasm caused by the beat of cilia.Cilia occur in pairs in epithelia of the gill, and members of pairs are fused at their distal ends.Each cilium, as seen in dark-field illumination, pierces its basal body, and the fiber that is a continuation of the cilium divides immediately below the basal body into two; one diverging to the right, one to the left.Each cilium is composed of many delicate fibrillae.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050400304
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  • 93
    Digitale Medien
    Digitale Medien
    The primordial germ cells of Hemidactylium and other amphibiaThe writer takes pleasure in acknowledging the helpful suggestions and criticisms of Profs. B. F. Kingsbury and S. H. Gage. To Professor Gage he is also indebted for the loan of a very complete series of Amblystoma embryos and larvae. Valuable assistance in the collection of other material was rendered by Profs. A. H. Wright and D. L. Gamble, of the Department of Zoölogy. Expenses incurred have been partially met from the Mrs. Dean Sage Research Fund. (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1925), S. 1-43 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The primordial germ cells of urodeles and anurans can occupy comparable positions in the embryo only in very early stages of development, if at all. When first recognizable as reproductive elements, their situation in the two amphibian orders is quite strikingly different.The germ cells first become recognizable in urodeles in the medial edge of the lateral mesoderm; there is no evidence that their position previous to this time is other than mesodermal. In the anura they are entodermal in association during early development; they are finally separated from the dorsal portion of the roof of the archenteron to form a single axial germ-cell cord. No amphibian species studied showed a mode of origin different from that characteristic of its order.The so-called migration of the amphibian germ cells to their definitive situation is interpreted as the result of growth shiftings of related parts. Germ cells do not migrate independently through the tissues. Aberrant or ectopic cells for the most part result from failures or faulty correlations of growth processes. Certain aberrant cells of the caudal portion of the body in urodeles indicate the inclusion of sex elements in the ventral as well as in the lateral mesoderm.
    Zusätzliches Material: 31 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410103
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  • 94
    Digitale Medien
    Digitale Medien
    Correlations of the musculature and the movements of the skull in natrix, with some suggestions of homology in the lacertiliansContributions from the Zoölogical Laboratory of the University of Illinois, no. 271. (1925)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1925), S. 159-181 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The musculature of the ophidian head is a fairly complex structure, due to the specialization of the skull and the peculiar movements and motions made possible by the high degree of streptostylism.This musculature has been derived from the lacertilian type by a splitting and a shifting of the original elemental muscle masses of this group. Most of the muscles are clearly homologous with those of the Lacertilia. Some cannot be homologized by a study of the mature forms.The greatest differences lie in the separation of the muscle masses in the ophidia, as compared with the undivided masses in the Lacertilia. Since the jaw movements of the Lacertilia are rather simple, there is no need for any subdivision or splitting of the jaw muscles, but with the complex movements of the ophidia this becomes necessary.A few of the ophidian muscles appear to be neomorphs, as no key to their origin could be determined by a comparison with lacertilians.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410107
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  • 95
    Digitale Medien
    Digitale Medien
    Masthead (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410201
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  • 96
    Digitale Medien
    Digitale Medien
    Egg formation in a leech (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 333-345 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In a leech infesting the Alaskan codfish germinal masses in the ovary proliferate secondary groups, comprising about forty cells in which a follicle and central supporting cell early differentiate. Active division results in approximately 500 cells which apparently develop ductules extending to a point on the surface of the egg. Granules of unknown origin then appear in each nurse cell, and are drawn down the ductules into the egg which can now be distinguished. Reasons are given for the belief that the nutritive material is drained from the nurse cells by amoeboid activity of the egg. In early stages the nutritive mateiral forms a loose reticulum which gradually becomes transformed into a more extensive network, persisting until the maturation divisions. In this latest period the follicle and nurse cells, which become shrunken as the ovum enlarges, usually are stripped off and soon disintegrate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410204
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  • 97
    Digitale Medien
    Digitale Medien
    Development of the pelvic fins of acipenser ruthenus. New data for the theory of the paired fins of fishes (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 547-579 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The pelvic fins of the ancestors of the Chondrosteoidei possessed a metameric musculature and their skeleton consisted of a large number of metamerically arranged cartilaginous fin-rays, to which were attached osseous lepidotrichia. Evolution has involved the concrescence of separate elements to form the basal cartilage, the proximal end of which forms the girdle of the fin; the loss of a number of the fin-rays, and the atrophy of distal elements of the rays. The adult Chondrosteoidei have retained the primitive fin structure which characterized the elasmobranchs of the Palaeozoic period and which has disappeared in recent forms.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050410208
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  • 98
    Digitale Medien
    Digitale Medien
    The life-cycle in the ciliate Didinium nasutum with reference to encystmentThis paper and a following paper were submitted to the Board of University Studies of the Johns Hopkins University in partial fulfillment of the requirements for the degree of Doctor of Philosophy. This investigation was undertaken at the suggestion of Prof. S. O. Mast, whom the writer wishes to thank for invaluable assistance and criticism, both in the experimental work and in the preparation of the manuscript. The writer likewise wishes to thank Prof. H. S. Jennings for helpful criticism in the revision of the manuscript. (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926), S. 1-21 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Three groups of pure lines of diverse clones of Didinium nasutum were maintained in isolation cultures for 778, 786, and 457 generations, respectively, without exhibiting any decrease in fission rate or any increase in encystment rate or death rate. These lines were supplied with Paramecium caudatum in such numbers that a surplus of food was present at all times.Three other groups of lines of the same clones were established simultaneously and cultured in parallel with the preceding groups, but the food of each of these lines was limited to nine paramecia per line daily. The fission rate of these lines fell to zero and the encystment rate increased to 100 per cent after 155, 165, and 113 generations of culture, respectively. The death rate increased appreciably in these lines prior to encystment.Other groups of pure lines were cultured on a diet limited to six paramecia per line daily. These lines encysted after approximately fifteen generations of culture.This evidence indicates that there is nothing in the nature of a definite life-cycle in Didinium and that diminished vitality and encystment do not result from the passage of generations, but from inadequate and unfavorable cultural conditions-specifically, from in-sufficient food. It shows further that it is possible to induce cycles with reference to encystment in Didinium by limiting the food supply and to vary the length of the cycles by varying the quantity of food.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050420102
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  • 99
    Digitale Medien
    Digitale Medien
    The comparative morphology of the secondary sexual characters of elasmobranch fishes the claspers, clasper siphons, and clasper glands. Memoir VIIIFigures 1 to 5 are by Micheal G. L. Perkins, the rest by Miss Edith C. Humphreys from the author's dissections, to both of whom best thanks are tendered. (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926), S. 307-320 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Chlamydoselachus resembles the Holocephali in possessing no siphon, but a cavity in the proximal portion of the clasper. The cartilages, musculature, and venous sinuses of the clasper are considered. An older specimen of Echinorhinus is proved to have a spine on a soft papilla; Scymnus has no spine; both have the general features of the Spinacidae. Two species of Cestracion are compared with C. philippi. Mustelus lunulatus lacks the pera and pseudosiphon of M. vulgaris. Dicerobatis has a peculiar scaphus, and the claspers end in a fimbriated manner. Pteroplatea resembles Trygon and Benthobatis and Astrape are both like Torpedo.The species are listed below.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050420109
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  • 100
    Digitale Medien
    Digitale Medien
    Parental chromosome dimensions in Ascaris. A study of the effect of cellular environment on chromosome size (1927)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 44 (1927), S. 117-125 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In the early cleavage stages of Ascaris the homologous chromosomes are of unequal length. Measurements show that these homologues fall into two sharply defined groups suggesting their biparental origin. The shorter are considered to have come from the male.As the age of the embryo increases, these differences between the chromosome mates tend to become less, and it is suggested that at some later period in the history of the animal this difference will entirely disappear in response to the effect of continued existence in a common environment. The length of the chromosomes is very slightly shortened during the early cleavage divisions, while the area of the equatorial cross-section of the cells becomes enormously reduced.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1050440106
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