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  • Life and Medical Sciences  (36)
  • Wiley-Blackwell  (36)
  • 1925-1929  (36)
  • 1910-1914
  • 1926  (36)
Collection
Keywords
Publisher
  • Wiley-Blackwell  (36)
Years
  • 1925-1929  (36)
  • 1910-1914
Year
  • 1
    Electronic Resource
    Electronic Resource
    The histology of the blood of perophora viridis (ascidian)The observations here recorded were made at the United States Biological Station, Beaufort, North Carolina. I wish to express my gratitude to Hon. Henry O'Malley, Commissioner of Fisheries, for the privilege of using the laboratory, and to Mr. Charles Hatsell, acting director of the station, for the many courtesies extended to me during the course of the work. (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 311-331 
    Details
    ISSN: 0362-2525
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050410203
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  • 2
    Electronic Resource
    Electronic Resource
    The germ cells of anurans. II. An embryological study of sex differentiation in Rana catesbeiana (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 441-546 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryological study of bullfrog tadpoles collected from various parts of the United States has shown the existence of local races which differ markedly in regard to the time of occurrence and character of the developmental processes involved in the formation of the definitive testis of the male individuals. Those races in which the gonads of the two sexes are easily distinguished in early larval stages are called differentiated. Other local races show a peculiar gonadic development chiefly affecting the males, the definitive testis sometimes not appearing until near the end of the second year of larval life. Such races are called undifferentiated, because the morphological features of the definitive testes are not established until late. The larvae first develop a peculiar gonad (progonad) which later degenerates and is replaced by the definitive testis. All male animals of the undifferentiated strains exhibit the gonad cycle.The progonad varies among the local frog races in regard to the length of persistence and degree of differentiation attained before undergoing degeneration. Its germ cells may exhibit a typical male maturation cycle ending in degeneration, or the cells may differentiate along both male and female lines or remain sexually neutral.The development and differentiation of the progonad in the various races are described and a detailed account given of the origin of the definitive testis. The problems of sex differentiation and continuity of the Keimbahn in anurans are discussed.
    Additional Material: 100 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050410207
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  • 3
    Electronic Resource
    Electronic Resource
    Masthead (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050420101
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  • 4
    Electronic Resource
    Electronic Resource
    The metabolic gradients of vertebrate embryos. II. The brook lamprey (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926), S. 111-141 
    Details
    ISSN: 0362-2525
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050420105
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  • 5
    Electronic Resource
    Electronic Resource
    The development of the premandibular head cavities and the relations of the anterior end of the notochord in the chick and robin (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 42 (1926), S. 371-439 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The prochordal plate in the chick is a thickening of the entoderm in the anterior part of the area pellucida. It consists at first of several layers of yolk-charged cells, which finally lose their yolk and form a thin layer of entoderm.The prechordal plate (an area of mesodermal proliferation immediately anterior to the notochord) arises immediately anterior to the primitive streak (and head process when the latter appears) in a part of the region once occupied by the prochordal plate. Later the prechordal plate comes to lie upon the dorsal wall of the foregut.The premandibular cavities arise in condensations of the prechordal mesoderm. The cavities seem to appear during the rapid expansion of the prechordal mesoderm which occurs in response to a release from constraint imposed by surrounding structures. They are connected with one another across the midline by a usually solid bridge of mesoderm.Later, the cavities are replaced by a mesodermal condensation which serves as a mold, on the surface of which the oculomotor muscles appear, arising before the disappearance of the premandibular head cavities.Differences in the relations of notochord and hypophysis in the chick and robin may be explained by an analysis of the growth of the two forms. The analysis furnishes a basis for understanding the relations of the anterior end of the notochord in the mammal.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050420203
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  • 6
    Electronic Resource
    Electronic Resource
    Masthead (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1926) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050430101
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  • 7
    Electronic Resource
    Electronic Resource
    The structure and division of paramecium trichium stokes (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 43 (1926), S. 81-103 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Paramecium trichium varies from 50 μ to 105 μ long with most individuals between 80 μ and 90 μ. The width varies from one-third to one-half the length. It is somewhat depressed dorsoventrally. The broad buccal groove extends from the anterior left border diagonally across the ventral surface to the mouth, which is usually slightly anterior to the middle and to the right side of the median line. The mouth leads into a relatively long cytopharynx containing an undulating membrane. The cytopyge is subterminal and the small caudal tuft of longer cilia is subapical. The plastic ectosarc contains numerous trichocysts. A contractile vacuole apparatus occurs near either end. Each is deeply located and stains more intensely than surrounding protoplasm. In life there appear to be two alternately contracting vacuoles with smaller ones adjacent. Contractions are from fifteen to twenty-five per minute. The macronucleus is medium in size and the single micronucleus is of the ‘caudatum’ type.Binary fission appears to be initiated by a metaphase-like condition of the micronucleus. This is followed by great enlargement and the eventual separation of the chromatin threads into two anaphase groups. The metaphase thus appears to precede the changes which correspond to a prophase in other cases. During division of the body, the two old contractile vacuoles persist as the posterior ones for the daughters, new anterior ones being developed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050430105
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  • 8
    Electronic Resource
    Electronic Resource
    Masthead (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050410201
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  • 9
    Electronic Resource
    Electronic Resource
    Egg formation in a leech (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 333-345 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a leech infesting the Alaskan codfish germinal masses in the ovary proliferate secondary groups, comprising about forty cells in which a follicle and central supporting cell early differentiate. Active division results in approximately 500 cells which apparently develop ductules extending to a point on the surface of the egg. Granules of unknown origin then appear in each nurse cell, and are drawn down the ductules into the egg which can now be distinguished. Reasons are given for the belief that the nutritive material is drained from the nurse cells by amoeboid activity of the egg. In early stages the nutritive mateiral forms a loose reticulum which gradually becomes transformed into a more extensive network, persisting until the maturation divisions. In this latest period the follicle and nurse cells, which become shrunken as the ovum enlarges, usually are stripped off and soon disintegrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050410204
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  • 10
    Electronic Resource
    Electronic Resource
    Development of the pelvic fins of acipenser ruthenus. New data for the theory of the paired fins of fishes (1926)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 41 (1926), S. 547-579 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pelvic fins of the ancestors of the Chondrosteoidei possessed a metameric musculature and their skeleton consisted of a large number of metamerically arranged cartilaginous fin-rays, to which were attached osseous lepidotrichia. Evolution has involved the concrescence of separate elements to form the basal cartilage, the proximal end of which forms the girdle of the fin; the loss of a number of the fin-rays, and the atrophy of distal elements of the rays. The adult Chondrosteoidei have retained the primitive fin structure which characterized the elasmobranchs of the Palaeozoic period and which has disappeared in recent forms.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050410208
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