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  • Life and Medical Sciences  (655)
  • Roggen
  • AERODYNAMICS
  • Animals
  • 1930-1934  (367)
  • 1925-1929  (187)
  • 1920-1924
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  • 1
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 35 (1921) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 2
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    Journal of Morphology 36 (1922), S. 421-445 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 3
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    Journal of Morphology 36 (1922) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 4
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    Journal of Morphology 37 (1922) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 5
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    Journal of Morphology 37 (1923), S. 385-423 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 6
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 37 (1923) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 7
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    Journal of Morphology 37 (1923), S. 533-553 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 8
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    Journal of Morphology 38 (1923), S. 65-104 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 9
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    Journal of Morphology 38 (1923), S. 207-278 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 10
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    Journal of Morphology 38 (1924), S. 431-451 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 11
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    Journal of Morphology 38 (1924), S. 453-483 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 12
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    Journal of Morphology 38 (1924), S. 581-598 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 13
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    Journal of Morphology 37 (1923), S. 555-581 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 14
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    Journal of Morphology 38 (1923), S. 19-63 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 15
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 38 (1923) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 16
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    Journal of Morphology 38 (1924) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 17
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    Journal of Morphology 38 (1924), S. 387-429 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 18
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 19
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    Journal of Morphology 38 (1924), S. 529-549 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 20
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    Journal of Morphology 36 (1922), S. 400-419 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 21
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    Journal of Morphology 39 (1924), S. 285-293 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 22
    ISSN: 0362-2525
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  • 23
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    Journal of Morphology 37 (1923), S. 287-305 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 24
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    Journal of Morphology 40 (1925) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 25
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    Journal of Morphology 40 (1925), S. 517-557 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An early segregation of germ cells and migration through a germ track into the gonad does not occur in the albino rat. The germ cells are produced only from the peritoneum of the genital region and their earliest formation is coincident with the thickening of the coelomic epithelium to form the genital ridge. This takes place eleven days after insemination in embryos of approximately 18 somites. Germ cells continue to form from the peritoneum during the early development of the gonad. The peritoneum of this region also produces mesenchyme, smaller cells of the gonads, and the germinal epithelium.The argument for the specific character of the germ cells in vertebrates and their continuity from the egg is based largely upon assumption, and not upon substantial observations, and must be discarded. Germ-cell origin is a problem of cellular differentiatio, and not of early segregation.
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  • 26
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    Journal of Morphology 41 (1925), S. ii 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 27
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    Journal of Morphology 41 (1925), S. 191-216 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Painted turtles, gopher tortoises, and terrapins were fed on various mixtures of sand, salts, dextrin, casein, cod-liver oil, wheat, eggs, lettuce, and meal worms. Each individual was weighted weekly for about a year and then killed for analysis, the water, ash, nitrogen, and fat being determined. Some individuals increased in weight as much as 75 per cent, others lost weight. Judged by growth and chemical analyses, the food requirements of chelonians, as representative poikilothermal vertebrates toward nutritive substances (including vitamines) are similar to those of homoiothermal animals.
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  • 28
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    Journal of Morphology 41 (1925), S. 267-281 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Of the eggs laid by Fasciolaria about 1 per cent develop into veligers, about 2 per cent more undergo a few cleavage divisions, and about 97 per cent do not divide at all. The 99 per cent that fail to develop normally are ‘swallowed’ by the veligers. This study concerns itself chiefly with the ova that do not divide. Notes on normal development and on the ova that undergo atypical cleavage are included.All of the ova are found to be typical when passed from the ovary. To each ovum one to several sperms become attached at the vegetal pole in the region of a mass of undifferentiated protoplasm - the ‘polar mass.’ A fertilization cone forms in each ovum and a fertilization membrane. In typical development a yolk lobe is formed, the sperm enters in the usual way, and fertilization is completed as in many other mollusks. In 97 per cent of the ova the yolk lobe is not formed and the sperm does not enter. In these cases the wall of the egg nucleus remains intact a long time. The nucleus itself and the ‘polar mass’ sink into the egg and meet at the center. Then the nuclear wall disappears and an atypical diaster is formed. However, cleavage is not begun and the chromosomes form vesicles that remain near the center of the ovum until it is ‘swallowed’ and digested by the veliger.
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  • 29
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 30
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    Journal of Morphology 42 (1926) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 31
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    Journal of Morphology 42 (1926), S. 111-141 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 32
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    Journal of Morphology 42 (1926), S. 83-109 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The summary of this paper is as follows:1A critical review of the developmental evidence shows that the branchial pouches are formed in cephalocaudal sequence subsequently to the segmentation of the dorsal mesoderm.2The pouches interrupt a continuous sheet of mesoderm to form the branchial arches.3The arches when formed do not correspond topographically to the dorsal somites.4Branchiomerism does not therefore coincide with somitic metamerism.3The branchial structures do not support the theory of head segmentation.3The nervi trigeminus, facialis, glossopharyngeus, and vagus cannot be regarded as segmental nerves.3There is no evidence that branchial pouches or arches have been elided from the series.3The problem of meristic homology is briefly discussed.
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  • 33
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    Journal of Morphology 33 (1920), S. 388-437 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
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  • 34
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    Journal of Morphology 33 (1920), S. 526-583 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
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  • 35
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    Journal of Morphology 34 (1920), S. 68-117 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 36
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    Journal of Morphology 43 (1927), S. 521-546 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 37
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    Journal of Morphology 44 (1927), S. 1-20 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 38
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    Journal of Morphology 44 (1927), S. 117-125 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 39
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    Journal of Morphology 44 (1927), S. 313-339 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 40
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    Journal of Morphology 44 (1927), S. 363-372 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The history of investigations on the contractile vacuole is reviewed briefly and brought up to date.The study of the contractile vacuole in Amoeba proteus is considered from standpoints of origin, structure, behavior, and function. The results are obtained from a prolonged study of normal organisms and from their reactions when introduced into conductivity water.The origin of vacuoles is studied by means of dark-field illumination which reveals the vacuole to be formed from a fusion and coalescence of extremely minute droplets.The retaining ‘wall’ of the contractile vacuole is not a permanent structure, but is in the nature of a condensation membrane, totally disappearing with each contraction.The loci of the contractile vacuoles are not permanent, but vacuoles are formed more or less at random. It is unlikely that they are supported in gelated areas, for amoebae with a dozen vacuoles are quite active and there is no interference with amoeboid movement.Conductivity water increases the size, number, and rate of contraction of contractile vacuoles, which suggests that they may function in maintaining an osmotic gradient as well as in the elimination of metabolic waste.
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  • 41
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    Journal of Morphology 44 (1927), S. 467-514 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The eggs of Corella develop in the atrial chamber of the parent at a pH below that of normal sea-water (pH 7.4 ±). When removed to normal sea-water in early stages and under certain other experimental conditions, larval development is more or less inhibited, the tail being most inhibited, the dorsal region somewhat less. The free larval stage may be eliminated and later development and metamorphosis may proceed normally to an advanced stage in the chorion and give rise to normal ascidians. The region most inhibited are, in general, those which possess the highest reducing power, as indicated by KMnO4. Experiments made in the attempt to control development all agree in indicating that the early stages are adjusted to a certain CO2 concentration approximately that of the atrial chamber and presumably near that of the body. Solutions of the same pH may or may not inhibit development according to their CO2 content.The tail, the region of highest reducing power in the embryo during its development, is most inhibited; the dorsal region, the next most rapidly reducing region, is next in degree of inhibition. All differences in reducing power disappear when, or soon after, the animals are killed by other agents before treatment with KMnO4.
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    Journal of Morphology 39 (1924), S. 267-283 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Morphology 39 (1924), S. 337-349 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Morphology 39 (1924), S. 435-463 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 45
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 46
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The claspers of Centrina are adnate with the pelvic fin and bear a spine as in other Spinacidae. Mustelus canis resembles M. lunulatus rather than M. vulgaris. The claspers of Chiloscyllium end in a pointed spike. Pseudotriakis resembles the Carchariidae. The three North American Atlantic species of the genus Raia are considered, and R. laevis and R. erinacea are placed in the pseudogenus containing R. batis, and a new pseudogenus erected for R. ocellata. A gross and histological account is given of the Cowper's glands of Homo, and they are shown to be homoplastic with clasper glands, similar in structure, arrangement, development, and function.
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  • 47
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: In the golden-mantled ground-squirrel, Callospermophilus, a spatulate glandular area has been noted in the skin of the back. It has been found in the following species: C. l. lateralis, C. l. arizonensis, C. l. caryi, C. l. saturatus, C. l. tescorum, C. c. chrysodeirus, and C. bernardinus. Probably it is common to the genus.The individual glands making up this area are modified and enlarged sudoriparous glands. They are divided into a tightly coiled and branched fundus, a large sinus, and a duct which passes caudad and outward to its exit at the surface.The glands secrete a strongly smelling oil, which is probably left on vegetation and other objects in the animal's environment and serves as a source of information to other members of the species. The glands are more active in spring and summer than in winter. They are stimulated by excitement. While present in both sexes, both adult and juvenile, they are best developed in adult males.Callospermophilus has three anal glands. These have flat-topped, straight-sided nipples which are protruded from the anus if the animal is frightened. A milky substance with a very weak odor can be extruded.
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  • 48
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: The study is divided into three parts. Part I deals with the chromosome number and morphology in the amniotic cells of rabbit embryos. The number of chromosomes has been found essentially constant in amniotic cells of young, but more variable in older embryos. The somatic number is 44. Part II deals with the chromosomes of race crosses (Flemmish Giant X Polish) in which the homologous chromosomes were found to be alike. Part III deals with spermatogenesis. There are forty-four chromosomes in spermatogonia, and twenty-two in primary spermatocytes. The sex chromosomes are of the usual X-Y type.
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  • 49
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    Notes: 1Monovalent cation salts induce reversal in the direction of the stroke of the cilia; bivalent and trivalent cation salts with a few exceptions do not. Some acids induce reversal, others do not.2The duration of reversed action varies with the kind of salt and with the concentration. As the concentration increases, the duration of reversed action increases to a maximum and then decreases to zero.3Bivalent and trivalent cation salts neutralize the effect of monovalent cation salts. The relative amount required varies with the kind of salt used and with the concentration.4The amount of a given salt required to neutralize another salt is not proportional to the concentration of the salt neutralized. Weber's law does not hold.5The results seem to indicate that ciliary reversal is associated with differential adsorption and consequent changes in electric potential, but that there are also other factors involved.
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  • 50
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A special type of cell, called ‘Lichtzellen’ by Hesse, was found in the photosensitive regions of the earthworm. Wherever the epidermis is most sensitive to light these cells are most abundant. They are found in the epidermis of all segments of the body and also in nerve enlargements of the prostomium and the caudal segment, but the intersegmental and ventral regions of the different segments, except the more distal ones, contain none of them. They are supplied by nerves and each contains a characteristic inner structure, the optic organelle, composed of a large central hyaline structure, the lens, which is surrounded by a dense network of nerve fibrillae, the retinella. In hanging drops the lens was found to focus light in the region of the retinella irrespective of the direction of the rays.These cells are similar in structure and function to the visual cells in leeches. Available data indicate that these cells function as photoreceptors and that the fibrillae of the retinella are the direct receptors of light stimuli.Pigment is not associated with the photoreceptors in a way that suggests direct functional relationship, but there is a subepidermal pigment layer through which pinhole windows admit light along the path of nerves to each of the nerve enlargements containing photoreceptor cells. These windows open in such directions as to determine the direction of withdrawal of the worm.
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  • 51
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of removal of the liver has been noted in fishes, frogs, and turtles. As in the higher vertebrates, removal of the liver produced a fall in blood sugar and a loss in muscular tone. The lower vertebrates failed to respond to intravenous injections of glucose, as do the birds and mammals. They also fail to respond to maltose or levulose. The liver maintained the blood-sugar level in the lower vertebrates, which is necessary for the maintenance of life.The mechanism of carbohydrate metabolism in the lower vertebrates may be different from that in the higher ones, in that glucose, when injected intravenously, apparently exercises a progressively less beneficial effect on the characteristic hypoglycemic condition which follows the removal of the liver of mammals and cold-blooded vertebrates.
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  • 52
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    Journal of Morphology 41 (1925), S. 239-265 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper reports experiments with Fundulus heteroclitus to modify larval development by means of ultraviolet radiation. Eggs were exposed to radiation at various intervals after fertilization for varying periods of time. The results accord with previous work on fish teratology, and the developmental types obtained are essentially similar to those produced by chemicals, cold, and hybridization. The deviations from normal development occur in the same body regions as do those in other vertebrates whose early development has been modified by the action of radiation (x-rays, radium, etc.).The results of these experiments indicate that there is a non-specificity in susceptibility relations with the production of similar types of monsters for widely different reagents. That these eggs are differentially susceptible to the action of ultraviolet radiation is indicated by the fact that those regions which have the highest metabolic activity when an inhibiting influence is active are the ones most generally affected. Thus modifications of the nervous system, sense organs, circulatory system, tail region, and body axis result, respectively, in the production of varying degrees of cyclopia, inadequate circulation, short, stubby or bent, non-motile tails (some bifid), and anterior twinning.As these modifications may be produced by applying inhibiting influences during the first few minutes after fertilization, it is evident that there is in the egg at this stage some constitutional or physiological basis which determines early differences in susceptibility of its various parts.
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  • 53
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    Journal of Morphology 41 (1926), S. 427-439 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Webbing of toes or fingers in man is produced by a local arrest of development, causing retention of the normal embryonic webbing. This type of digital fusion involves only the skin, the skeleton being unaffected. The extensor tendons of the toes may sometimes be fused.Webbed digits occur normally in some marsupials, rodents, and insectivores, in a number of lemurs and catarrhines, and in the siamang and gorilla. They also may occur in varying degree in other Primates, notably Hylobates. An analysis of five new pedigrees together with those already published demonstrates that webbing of toes in man may be inherited in either a mendelian or sex-linked manner. In one case this character follows the course of the Y-chromosome.
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  • 54
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    Journal of Morphology 45 (1928) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 55
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Amoeba proteus was raised in a modified and diluted Ringer solution. When the pH of this culture medium became less than 6.0, the normal activities of the amoebae were interfered with; and when a still lower pH was attained, the amoebae died off. The same was true when the pH became greater than 8.0. At neutrality the activities were subnormal, very dark, and rounded. The rate of locomotion of amoebae raised in solutions with a pH less than 7.0 showed a maximum rate of locomotion at pH 6.6, which decreased as the pH changed in either direction, dropping to a very low rate at pH 7.0 and above and also below 6.0. For amoebae raised at a pH above 7.0 the rate was maximum at pH 7.6 and decreased as the pH changed in either direction; it was low at pH 7.0 and below and also above 8.0.On increasing the external osmotic pressure of the medium it was found that the effects caused varied somewhat with the hydrogen-ion concentration. Small increases in osmotic pressure decreased the rate from the normal at pH 6.0 and 8.0, increased it at pH 6.6 and 7.6, and did not affect it at pH 7.0. Osmotic pressures above that produced by M/20 lactose caused locomotion to cease in a short time at all pH values.
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  • 56
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    Journal of Morphology 45 (1928), S. 209-231 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The highly specialized cranial musculature of the toadfish is characterized by the following features: 1Absence of intermandibularis and branchiomandibularis muscles.2Presence of levator premaxillaris muscle.3Very large branchial chamber, the outer wall of which is formed by seven branchiostegal rays connected by a strong fascia provided with muscles (oblique levators and adductors).4Highly developed masticator muscles (adductor mandibularis and pterygoids).5The rectus abdominis, sternohyoid, and hyohyoid muscles are attached by a median aponeurosis to the hyoid and basibranchial elements and directly to the hypobranchial cartilages; this muscle complex depresses the buccal floor in opposition to the geniohyoid.6The pelvic fins are in the jugular position.7Two narrow muscles connect the cleithrum with the fourth ceratobranchial.8The cranial musculature is obviously adapted to a carnivorous habit and particularly for increasing respiratory capacity under asphyxial conditions.
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  • 57
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    Journal of Morphology 45 (1928), S. 293-398 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Blindfolded persons walk, run, swim, row, and drive automobiles in clock-spring spiral paths of greater or less regularity when attempting a straightaway. The spirals turn either right or left in one and the same individual, and may do so even in one experiment. But either right or left turns predominate in the great majority of individuals, often to a high degree. The paths show marked individuality, and there is some ground for thinking there exists a correlation between temperamental differences and general character of path.The mechanism which produces the spiral path is not located in the locomotor organs, but in the central nervous system and is probably identical essentially with the spiral mechanism in other motile organisms, all of which move in spiral paths when there are no guiding senses to direct the path. The clock-spring spiral in man is interpreted as the expression in two dimensions of space of a helical spiral mechanism which seems to exist in all motile organisms moving in three dimensions of space and in amebas which move in two dimensions. In a large number of lower organisms the number of body lengths per spiral turn is almost constant, being about 4.5. The smallest regular swimming spirals in man are very close to this value, but the smallest regular walking spirals are somewhat larger. The fundamental spiral mechanism seems to be of molecular dimensions, and there seems to exist a demonstrable locomotor bilateral asymmetry in very nearly, if not quite, all organisms.
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  • 58
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    Journal of Morphology 45 (1928), S. 473-503 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A detailed study has been made of the anatomy of one of the fingernail shells, and preliminary observations on the life-history have been carried out. In its general organization Sphaerium notatum is very similar to the larger fresh-water lamellibranchs. A gastric shield, crystalline style, and style sac, very similar to those found in the stomach and intestine of Lampsilis, are present. A pair of slender muscles extending from the dorsal side of the body into the gills, and evidently not previously described, have been found. The nervous system consists of the typical three pairs of lamellibranchiate ganglia, with their connectives, accessory ganglia, and nerve fibers. Particular study was given to the statocysts and osphradia, and attention is called to the fact that the function commonly ascribed to the osphradia is incompatible with their position in the roof of the cloacal chamber.S. notatum, like all the Sphaeriidae, is hermaphroditic and viviparous. The gonads are paired racemose glands lying behind and below the stomach. The sperm-producing follicles form the anterior portion of each gonad and are somewhat smaller and more numerous than the ova-producing follicles which form the posterior portion. The young pass through the early stages of development in brood pouches in the gills and are expelled as relatively enormous individuals.Preliminary observations on the life-history indicate that reproduction reaches its height in the summer and that fertilization probably takes place during the late summer and fall.
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  • 59
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    Journal of Morphology 45 (1928), S. 579-597 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When Menidia eggs are fertilized with Prionotus sperm, the Prionotus chromosomes react in the Menidia cytoplasmic medium just as they do in the cytoplasm of Fundulus eggs. There is lagging, non-disjunction, and elimination of chromosomes during the early cell divisions. The mitotic behavior of the Prionotus sperm in the Menidia egg also resembles the behavior of the sperm of Ctenolabrus in the same medium. This behavior which was expected from what was known concerning the mitotic behavior of the reciprocal crosses between Menidia and Fundulus and between Ctenolabrus and Prionotus and other intercrosses between the members of these two groups is regarded as a function of the physical state of the egg cytoplasm during the division phase of mitosis. This physical character forms the earliest differential factor in the development of these hybrids and shows no correlation with the width of the cross.A comparison of nine teleost crosses, in which both the development and the early mitotic behavior are known, with a rough numerical estimate of the width of the cross brought out the fact that development is most successful in crosses between nearly related species if mitosis is normal and in distantly related crosses if mitosis is abnormal. This indicates that nuclear relationship is also a factor in the development of hybrids.
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  • 60
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    Notes: Virulent hay-infusion cultures of Bacillus pyocyaneus are toxic to pure-line races of three species of paramecia, but these races may acquire a tolerance for this toxic agent. Races with acquired tolerance have been grown for long periods of time in toxic, pure cultures of B. pyocyaneus by means of the daily-isolation culture method, and here the average division rate is as high as, or higher than, in the chance-mixed bacterial cultures in which these protozoa are usually maintained in the laboratory. The tolerance is lost, however, when the paramecia are removed from the toxic cultures and grown for a number of generations in cultures of non-toxic bacteria.The toxic agent that is lethal to paramecía is probably the soluble toxin of B. pyocyaneus. The investigation shows that the agent is soluble and either thermolabile or volatile. It also shows that all deleterious substances, other than the soluble toxin, known to be produced in cultures of this bacillus, are non-lethal to paramecia.Hay-infusion cultures of Bacillus enteritidis were lethal to paramecia. All attempts to develop tolerance in paramecia for the toxic agent in these cultures failed.Under the experimental conditions that prevailed, diphtheria toxin was found to have no appreciable effect upon the division rate or death rate in three species of paramecia.
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  • 61
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    Journal of Morphology 49 (1930), S. 385-413 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure of the living blood cells is described and the cells are classified in the following species of ascidians: Phallusia nigra, Ecteinascidia turbinata, Clavelina oblongata, Symplegma viride. Evidence for the genetio relationship of the various types of cells is discussed.
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  • 62
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    Journal of Morphology 49 (1930), S. 455-507 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The history of the cytoplasmic components in the spermatogenesis of Gerris is, in general, like that which has been described in the Pentatomidae. The observations of fixed material have been checked by extensive studies of freshly teased preparations. During the spermatocyte growth period the chondriosomes undergo considerable increase in mass. During the maturation divisions the chondriosomes are remarkably constant in orientation with respect to the centrioles. The nebenkern arises by fusion of chondriosomes differentiated into chromophilic and chromophobic portions. The Golgi bodies of the earlier spermatocytes are vesicular bodies, the peripheries of which are osmiophilic. These are not visible in fresh preparations, but the masses resulting from their fusion in the late prophase of the first division are visible in the unfixed cells. The non-osmiophilic material inside these masses stains with neutral red in fresh preparations. Only the osmiophilic part of the Golgi masses is involved in the fragmentation to form dictyosomes. There is very suggestive evidence that the process of acrosome synthesis largely takes place inside the sac-like acroblast (Golgi apparatus). In the spermatid, material which stains, in fresh preparations, like the acroblast is never seen, except inside or attached to the acroblast, where it appears in the form of small spheres of ‘pro-acrosomic’ material, which fuse to form the acrosome.
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  • 63
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    Journal of Morphology 49 (1930), S. 579-619 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Haemichromis bimaculata is a tropical teleost fish which will produce eggs practically throughout the year at intervals of from three to four weeks. These eggs are of suitable size and character for embryological study, the features of special interest so far discovered being as follows: (1) The egg is oval; (2) it is attached to a substratum by its side, the blastopore being at one end; (3) the embryo always tends to develop along the side opposite that originally next to the substratum.Results obtained by reorienting the eggs previous to cleavage, and by centrifuging them, seem to show that the relation of the embryonic axis to the egg is determined either previous to laying or very soon afterward, possibly by the relation to the substratum, and is not subsequently affected by gravity or other known factors. There may be some tendency for the first cleavage plane and the sagittal plane of the embryo to coincide, but such coincidence is not at all constant or exact.
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  • 64
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    Journal of Morphology 50 (1930), S. 127-142 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Color changes in Palaemonetes had been found to be inhibited in the whole abdomen by occluding the dorsal abdominal artery. Inasmuch as these chromatic responses are brought about by means of circulating hormones, it should be possible, in view of early anatomical findings, for specific substances to reach the abdomen by way of the ventral abdominal artery which has been described for so many decapod crustaceans. This paper reports a degenerate ventral abdominal artery and a ventral continuation of the dorsal abdominal artery, the latter thus being distributed to practically the entire abdomen and therefore chiefly responsible for abdominal color-change phenomena.A method is given for injecting the arteries of small crustaceans, and the entire arterial system of Palaemonetes is described and figured. Several hitherto unreported vascular structures are noted: a plexus of blood vessels surrounding the supra-oesophageal ganglion, certain branches of the ophthalmic artery leading to the eyes, and various branches of the dorsal abdominal artery in the region of the telson and uropods. The forward flow of blood in the ventral portion of the abdomen in decapod crustaceans is held to be unique.
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    Journal of Morphology 50 (1930) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 66
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    Notes: Histological changes which occur in the digestive system and its appendages and in the muscular system of the honeybee during metamorphosis are described. Some attention is given to changes which take place in the fat-body, the silk-glands, and the reproductive system. Material of known ages was used. Observations began with the sealing of the larva in its cell and were concluded with the young bee ready to emerge from its cell. Soon after the larva is sealed in its cell, the body tissues begin to undergo a change. Larval epithelial cells lining the midgut are cast into the lumen and they are replaced by cells which proliferate from the imaginal or ‘replacement’ cells. In the fore- and hindgut the lining of the larval cells is replaced by imaginal cells whose points of origin are probably at the anterior and posterior ends, respectively, of the midgut. While the imaginal lining is being formed, the opening from the midgut into the hindgut is closed by a small portion of tissue. A part of the larval muscles are histolyzed and then re-formed from imaginal myoblasts, other larval muscles disappear entirely. The strictly imaginal muscles (e.g., leg muscles) are formed by myoblasts which congregate at the point of muscle formation. There is no evidence of phagocytosis in the honeybee during metamorphosis.
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  • 67
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    Journal of Morphology 50 (1930), S. 341-359 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth of chick embryos of heavy and light breeds and the reciprocal crosses between them is described. The embryos of the heavier breed and the hybrids were found to be somewhat heavier than the embryos of the lighter breed from the tenth day of incubation to hatching time. In eggs of the same weight from the two breeds the size difference tends to disappear toward hatching time, probably due to the equivalence of the strictly limited food supply. It is pointed out that the size difference is more probably due to difference in the proportion of cells dividing at a given time than to a difference in duration of mitoses.The mortality of the hybrid embryos was intermediate between that characteristic of the parent breeds, while the percentage of monsters in the hybrids was less than that for either parent breed. There is thus some indication of heterosis.
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  • 68
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    Journal of Morphology 50 (1930), S. 475-495 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Four species of iceryine coccids have been studied cytologically in connection with certain breeding experiments. These are Icerya littoralis, Icerya montserratensis, Echinicerya anomola, and Crypticerya rosae. For the three first-named species the complete chromosomal history has been established, and the evidence on the fourth, Crypticerya rosae, is sufficient to indicate that it differs in no essential respect from the others. The following résumé may, therefore, be considered to apply to all four species. The females are diploid, with a chromosome number of four, and the males are haploid, with a chromosome number of two. Oogenesis proceeds quite normally; two tetrads are formed and two maturation divisions occur in which the chromosomes are reduced to two in each female pronucleus. All eggs undergo this reduction: if the eggs are then fertilized, the diploid number is thus restored and development into females ensues; if the eggs remain unfertilized, whether in the body of a virgin or of a fertilized female, they develop parthenogenetically, with no restoration of diploidy, into haploid males. The spermatogenesis of the haploid males involves a single meiotic division, demonstrably equational in character; the accompanying cytoplasmic division is suppressed, and from each of the binucleate spermatids thus produced two spermatozoa are formed. These conditions are contrasted with the functional hermaphroditism and haploid parthenogenesis of Icerya purchasi.
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    Journal of Morphology 50 (1930), S. 569-611 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study is based upon a close series of ontogenetic stages from cleavage until after metamorphosis.The so-called primordial germ cells, first differentiated in the lateral mesoderm, are traced to a definitive position in the genital anlagen. Careful counts of these demonstrated that they exist in larger numbers in the younger stages and that few of them ever reach the genital anlagen where they may form a small portion of the propagative cells.Evidence is presented that the majority of the germ cells are of somatic origin. From the earliest appearance of the indifferent gonad certain cells in the germinal epithelium have been observed which were increasing markedly in size and undergoing the various changes necessary in the transformation of small cuboidal or spindle-shaped peritoneal cells with oval nuclei into large germ cells with immense polymorphic or lobate nuclei. These cells are abundant in all older individuals. All the successive stages in the evolution of a somatic cell into a reproductive cell, involving as it does an increase in size, changes in shape, and a new distribution of chromatin material, are demonstrated.
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  • 70
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    Journal of Morphology 51 (1931), S. 147-193 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 71
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    Journal of Morphology 51 (1931), S. 243-289 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 72
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    Topics: Biology , Medicine
    Notes: 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.
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  • 73
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    Journal of Morphology 51 (1931), S. 597-612 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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).
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  • 74
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: 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.
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  • 75
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: The various stages in the life history of Cryptocotyle lingua are identified and described. Adults naturally occur in the intestine of fish-eating birds and mammals. They were experimentally obtained in the cat, white rat, and guinea-pig. The development of the miracidium was followed within the egg. Larval stages occur in the marine snail, Littorina littorea. The structure of the redia and cercaria is described in detail, and evidence is submitted to show that the cercaria is identical with Cercaria lophocerca Lebour, described from the same snail on the British coast. Penetration and encystment of the cercaria in the skin of the cunner were experimentally secured. Excystment of the metacercaria was obtained both in experimental animals and in vitro. The metacercariae were maintained in culture media for as long a time as is required for them to attain sexual maturity in the final host. The host relations and specificity of the parasite are discussed on the basis of infection experiments. The cercaria is compared with similar larvae and its taxonomic position determined.
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  • 76
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    Journal of Morphology 50 (1930), S. 497-515 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Our observations confirm the recent findings of Krjukowa ('29) on the specific character of the Golgi material in the salivary glands of the Chironomus larva and are therefore in disagreement with the findings of Parat and Painlévé ('24).The Golgi material in the salivary glands of the Chironomus larva is present as discrete bodies having the form of crescents, rings, and rods. These are evenly deposited throughout the gland and show no makred variation in number at different stages of the physiological activity of the gland.The mitochondria are present in the form of filaments frequently concentrated in the area surrounding the nucleus and at the periphery of the cell.Neutral-red staining was never observed to color the Golgi bodies. It is suggested that the neutral-red bodies may represent the secretory material. However, it is clear that, whatever the significance of the neutral-red bodies, they are not Golgi material. Accordingly, this evidence supports the view that the Golgi apparatus, mitochondria, and neutral-red bodies are morphologically distinct structures in the cells of the salivary glands of the Chironomus larva.
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  • 77
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    Journal of Morphology 53 (1932) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 78
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: 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.
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  • 79
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    Journal of Morphology 53 (1932), S. 97-131 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 80
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: 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.
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  • 81
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    Journal of Morphology 53 (1932), S. 345-365 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 82
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    Journal of Morphology 53 (1932) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 83
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    Journal of Morphology 53 (1932), S. 443-471 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 84
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    Journal of Morphology 53 (1932), S. 473-497 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: By statistical analysis and microscopical examination of a series of monthly quantitative collections, an attempt has been made to interpret the life history and reproductive habits of Sphaerium solidulum, one of the numerous species of the genus Sphaerium.Individuals of the species under observation have a distinctly limited life span of approximately one year. The period of maximum reproduction of this species does not occur in the summer months, as previously believed, but in the winter months. Seasonal growth rings are not present on this shell, although concentric lines are characteristic. No individuals of maximum size were present during the months from August to February. Maximum-size adults are apparently sterile. The analysis of distribution curves of each quantitative sample indicates two size groups in each collection as shown by the bimodal character of each graph. Distribution curves of embryos feature the bimodal character of the young and adult. The conclusions are founded on data secured from twelve monthly collections made from the same habitat totaling 7022 individuals.
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  • 85
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    Journal of Morphology 54 (1932), S. 69-151 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although the egg of Amphioxus is much more fluid and less stereotyped than that of Ascidians, the poles, axes, and localizations of formative materials are much the same in the two. The spermatozoon enters near the vegetative pole and a peripheral layer of granular cytoplasm flows to this pole and later forms a crescent around the posterior side parallel to the first cleavage amphiaster; this is the mesodermal crescent. On the anterior side a similar area later gives rise to the chorda-neural crescent. Above these crescents is the ectodermal area, below them the endodermal area. The early cleavages divide these crescents and areas just as in Ascidians. The coeloblastula is at first spherical, but later flattens in the region of the mesodermal crescent; this flattening extends forward on the vegetative side to the chorda-neural crescent, where the invagination is sharpest. The blastopore is at first triangular in outline, the dorsal lip being formed by the chorda-neural crescent and the lateral lips by the mesodermal crescent. Later the chorda and the mesodermal crescents are infolded, the lateral lips fuse to form the ventral lip which grows dorsalward, the blastopore becomes wider from right to left than dorsoventrally, the gastrula elongates and in the angles between dorsal and ventral lips the mesodermal crescent forms the mesodermal grooves in the lateral walls of the gastrocoel.
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  • 86
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    Journal of Morphology 54 (1932), S. 221-231 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: What appears to be a variety of Macrostomum tuba has been described in this paper. There is but a single retinula in each eye. This visual cell displays three regions: rhabdome, ellipsoid, and myoid, as does a vertebrate's retinula. Moreover, the accessory pigment associated with the retinula of M. tuba is applied to the rhabdome and not to the ellipsoid and myoid; this likewise is similar to the distribution of the pigment about the vertebrate's retinula. An analogy, therefore, may be drawn between the visual cell of the rhabdocoele and that of the vertebrate. This is so strong as to suggest homology. Several features peculiar to this variety are: first, the chitinous, distal ring of the penis; second, the fact that shell and yolk droplets seem to be elaborated by each cell destined to become an oocyte.
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  • 87
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: By means of the ‘intravitam technic’ developed by Baumgartner and Payne (1931), the mature or maturing sperm of Chortophaga viridifasciata have been traced from the follicle of the testes in the male to the locus of fertilization in the female. The sperm aggregated into bundles, and held tight by a hyaline cytoplasmic cap, spiral up the follicle, turn and spiral back to the vas deferens by means of a periodic lashing and writhing of the sperm tails.The genital tract is described briefly. In the vasa deferentia and storage tubules, the sperm bundles are usually in a quiescent state, having been inactivated most probably by secretions from the tubules.Peristalsis and currents in the fluid contents of the tubules move the inactivated sperm from the vesicles of the male to the seminal receptacle of the female, where the cytoplasmic caps gradually disintegrate. This permits individual sperm to pass down the seminal duct and fertilize the ovum just before oviposition.Single photomicrographs and a series of photomicrographs show the sperm in various parts of the genital system and making actual progress up a follicle. A stained preparation was used for only one of the photos. The other nineteen are from living unstained tissue. The intravitam observations are, most probably, more ‘vital’ than any heretofore recorded.
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  • 88
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    Journal of Morphology 53 (1932), S. 189-199 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper describes ultraviolet (λ = 2750 A) photomicrographs of resting and dividing chicken macrophages and fibroblasts and of erythrocytes and lymphocytes. The structures found in these photographs are compared with the ones brought out in fixed material by Feulgen staining and found to be essentially similar in appearance. A preliminary series of ultraviolet pictures is also shown of a single fibroblast passing through several of its stages of division.
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  • 89
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A simply constructed apparatus, which includes a cinema camera, is described for the recording of ciliary movements. From data for Modiolus demissus obtained by this method, it is concluded that the coordinating impulse is a propagated impulse which regulates the temporal and spatial relationships of ciliary contractility, that this impulse has to a certain degree a determinant effect upon ciliary inhibitory influences so that the area rendered inactive is a multiple of the ciliary wave length, that the coordinating impulse is transmissible through cells bearing quiescent cilia, and that it may act as a stimulus of sufficient strength actually to cause quiescent cilia to become active.
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  • 90
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    Journal of Morphology 53 (1932), S. 433-441 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Reviews the question of the origin of the midgut of insects with its diverse appearances and interpretations. Without doubt the midgut epithelium in some insects is derived from the lower layer, but in other insects from the tips of the stomodaeal and proctodaeal invaginations. The question of its origin seems to be “a function of the position within the whole,” and best understood from a standpoint of the time of determination of the parts involved. Maps illustrating the prospective significances of the principal types are included and discussed.
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  • 91
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: More than 3700 individuals of Viviparus contectoides from the Illinois River, near Peoria, Illinois, and from the Erie Canal in central New York, have been the subject of statistical and biological analysis as periodic quantitative samples to secure information on the life cycle. Sexes are easily distinguished through tentacular differences. Shells show marked sex dimorphism of size. Males reach a maximum height of 25 mm.; females may exceed 40 mm. Distribution curves, checked by experimental data on another species of the same genus, give evidence that males live normally about one year, while females may live three years. Differences in sex ratio are attributable to differences in life span and to changes in environmental factors producing aggregations of members of one sex.In central New York, the parturition period seems to begin to March and terminates in June. In central Illinois it extends from February into May. The uterus of a gravid female contains eggs, embryos, and shelled young in a graded series. At birth, the young shell contains one and one-half whorls and has a height of approximately 3.8 mm. Color bands are present on the shell three months before birth. Initial growth rate is extremely rapid. In less than three months the largest of the new generation are as large as the smallest of the parent generation. Graphs given show seasonal changes in the population.
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  • 92
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    Journal of Morphology 54 (1932), S. 1-67 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper describes the development of the prechordal plate and mesoderm of Amblystoma punctatum from the late yolk-plug stage to the stage of about nineteen somites.In the earliest stage described the prechordal plate is embedded in the roof of the archenteron and flanked on both sides by prechordal mesoderm with which it is fused. The characteristics and limits of the prechordal plate and mesoderm are discussed and the fate of both traced. It is demonstrated that the mesodermal cores of the mandibular arches are probably largely derived from the prechordal mesoderm which flanks the prechordal plate. The prechordal plate is later separated out of the roof of the foregut in a caudocephalic direction, giving rise to a median mass of mesoderm which expands laterally independently of the mandibular portions of the prechordal mesoderm to give rise to head mesenchyme lying largely anterior to the level of the hyoid arch. The expansion of this mesoderm is followed in some detail.The boundary between prechordal and notochordal regions is placed at approximately the boundary between the mandibular and hyoid arches.The question of the interpretation of the prechordal region is briefly discussed.
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  • 93
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    Journal of Morphology 54 (1933) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 94
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: This investigation was undertaken to determine some of the variables involved in the demonstration of the Golgi elements. Gland cells of vertebrates were studied vitally, after impregnation by osmic acid methods, and after autolysis.The duration of the staining period and the concentration of the stain condition the results obtained by vital staining with neutral red. The success of impregnation of Golgi elements with osmic acid varies with,(1) the type of tissue, (2) the time of initial fixation in relation to the time of the death of the animal, (3) the position of the cell in the piece of tissue, and, (4) the temperature of incubation with osmic acid. Stages in the impregnation of Golgi elements can be followed by examining preparations of the same tissue at frequent intervals during the incubation period. An increase in the amount of material which reduces osmic acid and which may form Golgi elements occurs in the cells during autolysis.The results are interpreted as indicating that Golgi elements are visible products of chemical reactions that occur in cells. They represent localized regions containing particular classes of chemical compounds which may be present, as such, in living cells or result from transformations in the cells during incubation. It is suggested that for the cells under consideration these substances may be unsaturated fatty acids.
    Additional Material: 1 Ill.
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  • 95
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 54 (1933), S. 399-413 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The m. trapezius, with both brachial and branchial functions, is in seeming series with the mm. interarcuales laterales. The intrinsic muscles of the fin occur as a dorsal extensor sheet and three (or four) ventral flexor components. The spinal nerves, uncomplicated by extensive anastomoses, which supply the fin, clearly show that in the dogfish the fin muscles are derived not from dorsal and ventral elements, but from anterior and posterior, or protractor and retractor elements. The nerves prove that from the original protractor musculature only the anterior portion of the present flexor group is derived, while the original retractor musculature has become all of the extensor and the posterior part of the flexor series. Faradic stimulation of the live animal is satisfactory, although there is much variation in the sensitivity, particularly of different muscles.
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  • 96
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 54 (1933), S. 477-491 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mitochondria in the male germ cells of Sciara exhibit peculiarities as regards both morphological characteristics and distribution. In form. they show superficial similarity with those of some of the scorpions, while their distribution may be peculiar to the genus and depend on unusual meiotic divisions.
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  • 97
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 54 (1933), S. 459-475 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A description of the urogenital system in both sexes of Lepidosteus platystomus Rafinesque, and new observations on the blood supply to this system as well as to the rest of the viscera is given.The testes resemble the true piscine type. The sperm are carried by numerous vasa efferentia to the kidney tubules, through the mesonephros to the wolffian duct, and to the exterior as in the elasmobranchs and amphibians. The most anterior of the vasa efferentia are non-functional. The ovaries are simple sac-like structures continuous with their ducts. The oviducts transverse the ventro-lateral surface of the mesonephros, and enter into the dilated portions of the wolffian ducts, where they join, directly anterior to the urogenital aperture. There are no ducts in the male homologous with the oviducts of the female. The kidneys fused posteriorly, appear to extend the entire length of the body cavity, but the anterior third is non-urinary.By injection methods, the celiaco-mesenteric artery is shown to be crowded to the posterior end of the body cavity by the complicated swim-bladder, and runs anteriorly to supply the entire viscera. Its anterior portion is incorporated in the liver.
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  • 98
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1933) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 99
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1933), S. 29-51 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This article is an account of the complete musculature of an adult Neuropteran insect, Chrysopa plorabunda. Previous anatomical discussions on this order of insects include only a few of the muscles of the head and thoracic regions, while those of the abdomen are entirely lacking. The muscles here described include those of the head, thorax, and abdomen. The origin, insertion, and function of each muscle is given. The boundaries of several of the sclerites, especially those of the labium, are located by the observations on the musculature of these parts. The meso- and metathoracic wings are of the same size and for that reason the muscles of these regions are very much alike. The prothorax is greatly elonated, causing the muscles of that region to differ to a greater or less degree from the ‘general rule’ in insects. The abdominal muscles may be arranged in the several groups generally found in insects. In several cases, however, both the origin and insertion of the muscle have been shifted to accompany changes which have taken place in the abdominal segmentation. All of the muscles are shown in the four plates containing nineteen figures which accompany the text.
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  • 100
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1933), S. 131-135 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Photomicrographs have been made of grasshopper spermatocytes using ultraviolet light of several wave lengths. For studying chromosomes this wave length should be between ca 2800 A and ca 2500 A. With higher frequencies the entire cell becomes strongly absorbing and relatively little detail is to be seen. All cell structures, including the chromosomes, are as transparent to λ = 3500 A and to longer ultraviolet waves as they are to visible light. The present experiments do not indicate the exact point between λ = 3500 A and λ = 2800 A at which the selective chromatin absorption commences.
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