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  • Cell & Developmental Biology  (142)
  • ASTROPHYSICS
  • 1985-1989
  • 1980-1984
  • 1965-1969
  • 1950-1954
  • 1930-1934  (142)
  • 1934  (100)
  • 1931  (42)
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  • 1985-1989
  • 1980-1984
  • 1965-1969
  • 1950-1954
  • 1930-1934  (142)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    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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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    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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  • 3
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    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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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    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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  • 5
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    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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  • 6
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Each indifferent genital rudiment in the grasshopper embryo is composed of the following: (1) a terminal filament membrane; (2) an epithelial plate of indifferent cells, the dorsal cell mass; (3) the central cell mass containing germ and indifferent cells; (4) the ventral cell strand, and, (5) a delicate, investing membrane, the outer limiting membrane. It is roughly spindle-shaped in transverse section and extends from the first to the eighth abdominal segments.In the sexual differentiation of the genital rudiment the dorsal cell mass is retained as a definite embryonic rudiment in the female, but becomes an indistinguishable part of the central cell mass in the male.Ovarian development is initiated in the dorsal cell mass area, where cell aggregations are formed. Each aggregation is ultimately surrounded by the ingrowing outer limiting membrane to form distinct cellular columns. A latero-ventrad extension of this ingrowing process into the central cell mass continues the column formation process into the latter and results in the formation of a distally tapering structure composed of indifferent cells distad and germ cells and indifferent cells proximad. This structure constitutes the rudimentary ovariole which finally differentiates to form the terminal filament, germarium, and vitellarium.The ovarian portion of the oviduct and the tubular connection between the ovariole and oviduct are differentiated from the ventral cell strand.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 611-631 
    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 cellular relations between the prechordal mesoderm and the hypophyseal analage in duck embryos from the first to the eighth day of incubation.At nineteen somites the ectoderm destined to form hypophysis is seen as a plate of cells lying under the mesodermal mass anterior to the notochord. It extends anteriorly in intimate contact with the base of the forebrain, and posteriorly for about the same distance to the oral membrane. Following the lateral growth of the prechordal mesoderm and the rapid overgrowth of the forebrain, Rathke's pouch is definitely outlined. The upward expansion of the pouch, concomitant with the lagging of some of the prechordal mesoderm in the midline, effects a very close relation between these cells and those at the tip of the pouch. With the lateral expansion of the premandibular head cavities, some of the mesoderm adheres to walls of Rathke's pouch in the form of rods or knobs. As development proceeds the inherent growth tendencies of ectoderm and mesoderm express themselves differently and the rods or knobs become constricted off from the pouch, forming in its vicinity vesicles which exhibit a definite lumen.The question of an entodermal contribution to the hypophysis in this form is briefly considered.
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  • 8
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 51-58 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: By treating the clean skeletal tissue of an insect with concentrated KOH at 160° C., the contained chitin is converted to chitosan, and all pigmentation and admixtures are removed. The per cent distribution of chitin, expressed as chitosan, in the exoskeleton of the cockroach, Periplaneta fuliginosa, ranges from 37.65 in the dorsal abdomen to 18.22 in the hindwings. Other regions contain the following per cents: ventral abdomen, 37.11; metathoracic legs, 35.55; mesothoracic legs, 33.28; prothoracic legs, 32.24; pronotum, 31.55; head, 31.07; genitalia, 29.28; dorsal thorax, 29.07; ventral thorax, 28.33; antennae, 27.77; cerci, 25.65; and forewings, 19.99. Regional variations are constant in different individuals of the same species. The crop and gizzard contain 18.69 per cent; the hindgut, 18.15 per cent. The remainder of the alimentary tract contains no chitin. Traces of chitin are found in the trachea. No chitin is found in the egg-cases of this species. No correlation between chitin content and pigmentation or hardness is shown. Based on results from three trials, using thirty insects, the per cent of chitosan in the clean, dry chitinous material from the entire animal is 29.60; the per cent of chitosan based on the weight of the live animal averages 2.01.
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  • 9
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 325-337 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The purpose of this study was to learn something of the nature of the bead-like bodies which occur in the head of the sperm of the fowl since it was found in a previous study that they are apparently affected in a characteristic manner by vitamin E deficiency.Staining tests indicate that these bodies are composed of fats and fatty acids since they respond to osmic acid and Nile blue sulphate. They are also impregnated with silver nitrate and hence may be associated with the so-called Golgi materials of the cell.The beads first appear as a complete single row but subsequently they undergo fragmentation and redistribution. The whole process is probably a final transitory step in sperm transformation.The presence of this fatty material may signify that the sperm of the fowl, in contrast to that of most other animals, carries a store of food material to support its activity after liberation. The sperm may also be the carrier of a definite amount of vitamin E. Furthermore, the presence of this material may offer an explanation of the high resistance of the testis of the fowl to vitamin E deficiency because, since this vitamin is fat soluble, the testis as a whole would probably receive a disproportionately large share of the vitamin E stores of the individual.
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  • 10
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In sections from livers injected through the vascular system with Carter's carminegelatin or Berlin-blue gelatin masses at known, constant pressures, many cells were observed to contain ovoid or spherical bodies of the colored injection masses, similar to those described by Schäfer and his students, Herring and Simpson, as intracellular blood canaliculi.' In these livers practically all the cells were vacuolated. However, with livers injected with Berlin-blue gelatin mass dissolved in Locke's solution instead of distilled water, there were no intracellular masses and the cells appeared normal, though the sinusoids were completely filled with injection mass. The so-called ‘intracellular blood canaliculi’ described by Schäfer are interpreted as artefacts produced by a combination of factors, the most important of which is the difference in osmotic pressure. This is produced by the hypotonicity of the injection masses that are usually used, augmented perhaps by the effect of mechanical pressure used in administering the injection mass.Following impregnation of liver tissue by Golgi's rapid method, the usual network of intercellular bile canaliculi was revealed, but the presence of a permanent system of intracellular canaliculi was not observed. A few short, knobbed intracellular projections from the intercellular bile canaliculi were noticed; these probably represent the passage of secretion material into the intercellular bile canaliculi at the moment of excretion.
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  • 11
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The early developmental history of Sciuridae (squirrel family), from the ovarian egg to the establishment of the germ layers, was studied in fixed material comprising ova and embryos from six species of five genera. No significant differences were noted in the major processes of development in the six species. Continuous diminution in the size of the ova occurs from the beginning of follicular vesiculation up to the early blastocyst stages. Corpora haemorrhagica are present in most of the recently ruptured follicles of all the species.Cleavage is regular, though adequal, up to the eight-cell stage, the blastomeres clustering into a compact mass. There is desquamation of cellular material from the periphery of the ovum between morula and blastocyst stages. At the same time cells within the blastocyst degenerate to add to the cavity originally formed by confluence of intercellular spaces. The cavity forms among the inner cells, an inner cell mass being left at one pole and an anti-embryonic mass at the other. The anti-embryonic cells produce much of the yolk-sac entoderm and contribute to the implantation mass. The latter mass forms a temporary attachment of the blastocyst to the uterine mucosa in these species. The definitive entoderm arises by migration and delamination of certain of the inner cell mass cells. A transitory notochordal canal, passing in a vertical plane through Hensen's node, is strongly suggested.
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  • 12
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 56 (1934), S. 533-575 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The arterial system of Ptyas mucosus (Linn.) reveals the following interesting features: (1) A prominent diverticulum given off from the inner antero-dorsal edge of the left auricle. (2) Ridge-like continuation of the median hanging valve of the sinus venosus lining the ventral edge of the opening of the right precaval vein. (3) Guarding of the opening of the pulmonary vein by a portion of the inter-auricular septum abutting against it. (4) Presence of two longitudinal trunks on either side of the hepatic portal vein formed by the hepatic branches of the hepato-oesophageal arteries, which, uniting with one another, form a peculiar arrangement looking almost like a looped chain. (5) A complete arterial circuit in the female formed by the combination of the genital, supra-renal, and the anterior-most renal arteries of either side. (6) Chain-like arrangement formed by the alternate bifurcation and union of the posterior-most part of the longitudinal fat-body artery and also by its lateral branches, which unite with it here and there after giving off twigs to the fat bodies. (7) A pair of small arteries (or in some cases only one) called ‘arteria complexa’ which take their origin from the dorsal aorta opposite the openings of the iliac veins into the afferent renals.
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  • 13
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 55 (1934), S. 577-609 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An investigation has been conducted to ascertain the relationship of certain structures in the embryo of the grasshopper known as Melanoplus differentialis with reproductive organs in the adult male.The order of development of these structures was traced through the entire life history.It was determined that they are the rudiments of certain reproductive organs and that the knowledge obtained serves as an aid in more accurately classifying insects.
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  • 14
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 115-153 
    ISSN: 0362-2525
    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 series of ontogenetic stages from just before coelom formation to maturity.Primordial germ ceils are first seen at the outer edge of the lateral mesoderm and are traced from there to a position in the genital analagen. Counts indicate that most of them succeed in reaching the genital anlagen, where they from definitive reproductive cells in both sexes.The evidence seems to show that there is some transformation of somatic cells into germ cells in the immature female, but that this transformation is not extensive. In the male the primordial germ cells are the sole source of the definitive elements.
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  • 15
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The detailed spawning habits and hatching period are described. The larval period is divided into the inactive, when the yolk is the source of food, and the active period, when food is captured. The rate of growth and transformation of the larvae into fry is described.The cell formation passes into a syncytial period, when there are produced many nuclei without cytoplasm.c division. Around these nuclei, the cytoplasm collects to give rise to more cells. The method by which mucous cells are produced is described and also the presence of secretion masses in both the mucous cells and the syncytium of the mucosa.
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  • 16
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 52 (1931), S. 513-523 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The teleost fish Brachydanio rerio is strikingly marked with longitudinal black stripes, which extend into the caudal fin and across the anal fin. Removal of the anal fin is followed by complete regeneration of the fin and of its normal color pattern. Microphotographic studies show that melanophores are at first uniformly distributed in the regenerating tissue and that later the melanophores disintegrate in the zone of the future light stripe and increase in the region of the future dark stripe. Observations on the normal development of the fin where the history of the individual melanophores has been followed show the same mode of formation of the stripes.
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  • 17
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931) 
    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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  • 18
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 51 (1931), S. 545-595 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Study of living and sectioned material throughout the life cycle shows the germ-cell history from fertilized egg to sexual maturity. This can be divided into the following five periods with definite limits: Original appearance during cleavage, period of inactivity, period of multiplication, maturation, and fertilization. Primordial germ cells of characteristic structure can be recognized just before gastrulation, when there is one large germ cell in the mass of mesoderm on either side of the blastocoel. After one division in each of these two cells, the four daughter cells remain inactive, while the remainder of the mesoderm differentiates, until division is resumed in the developing gonad. An indefinite number of gametes is produced. All are direct descendants of the two original primordial germ cells. Transformation of somatic cells into germ cells does not occur nor do germ cells become somatic cells. Cell lineage shows the two primordial germ cells to be derived from the third division of the paired mesoderm cells which have arisen by an equal division of the fourth micromere produced by cell D of the four-cell stage. Details of meiosis have not been ascertained, because of the small size of the chromosomes, their large number, and the difficulty of fixation. Nothing forecasts which primordial germ cells will become ova and which spermatozoa.
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  • 19
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three types of cell inclusions are demonstrated within the general protoplasm of the binucleated Protoplina, parasites of Hyla aurea. These are considered to represent mitochondria, together with associated, synthesized vegetative granules and Golgi bodies, as evidenced by their behavior, morphology, and staining reactions.The Golgi material is shown to consist of irregularly twisted rods and granules scattered at random in the cytoplasm, but possessing a very distinctive morphology and reaction to different techniques when compared with the mitochondria. No relationship could be detected between these vegetative structures and the cilia, as has been previously described.These observations have also been extended to a similar study of the cytoplasmic organs of Nyctotherus cordiformis, and it has been possible to demonstrate Golgi bodies of a similar appearance within this organism as well as to show again the nature of the basal granules and their relationship to the cilia.The procedure of identifying the mitochondria elements with great care is recommended as a preliminary means of studying the Golgi apparatus of Protozoa, particularly where osmication techniques are used exclusively.
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  • 20
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: It is shown that in Prorhynchus applanatus there exists a type of yolk elaboration which has hitherto not been reported. Formation is within the nucleus through the growth and fusion of nucleoli, but the yolk globule becomes larger than the original nucleolus. The developing individual utilizes the food material contained in the yolk cells in the following order: (1) cytoplasm of the yolk cell, (2) yolk bodies contained in this cytoplasm, (3) intranuclear yolk, (4) nucleoplasm. It is also shown that the germ cells in this form arise from the endoderm by diapedesis, but that the yolk cells are mesenchymal in origin. The sequence of formation of male and female gametes precludes the possibility of the presence of sex hormones such as are found in higher forms.
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  • 21
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A comparative study has been made of fifteen species and subspecies of rodents to determine the range in number and variation in morphology of their chromosomes. The number range is between 40 and 86±, with an average number for known species of 52. In the family of Cricetidae there is little variation in chromosome number and a general similarity of the chromosomes. In the Muridae the range for known species is 40 to 42, but the chromosome morphology even of subspecies may be quite different. In Sciuridae a range of 48 to 62 has been found in different species. The greatest range in number is found in the Heteromyidae, 44 and 86± chromosomes having been found in two species. It is concluded that the stem number for rodents is close to 48 and that fragmentation and fusion account for variation in numbers, and these affect the morphology of the chromosomes. The evidence also indicates that variations in morphology are due to translocations and inversions, and possibly deletions accompanied by translocations.
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  • 22
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    Journal of Morphology 52 (1931), S. 429-483 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are in scorpions two sharply contrasting types in respect to the mode of distribution of the chondriosomes to the sperm cells. In one of these the chondriosomes, spheroidal in form and nearly definite in number, are sorted out whole without division during the spermatocyte divisions, their number being thus reduced successively to one-half and one-fourth. This type occurs in Opisthacanthus, Hadrurus, Vejovis, Euscorpius, and Palamnaeus. In the other, as yet known only in Centrurus, all the chondriosomes fuse during the spermatocyte growth period to form a single ring-shaped body; and this, during the two ensuing mitoses, is accurately divided into two, four, and eight equal parts, of which each spermatid receives two. In both types alike the chondrioma is thus distributed very nearly equally to the sperm cells, but by widely contrasting processes; and in both types the spermatid chondriosomes are drawn out to form the sheath of the axial filament in the sperm tail. In Opisthacanthus there are indications of a definite process of dictyokinesis during the spermatocyte divisions.These facts are discussed in the light of the general history of the chondriosomes in other animals, with especial reference to more general problems of cell division. The present vagueness and uncertainty of our knowledge of cell division and differentiation are emphasized.
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  • 23
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    Journal of Morphology 52 (1931), S. 593-607 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study is concerned with the interrelationship existing among the polymorphie soldier castes of six representative subgenera of the genus Nasutitermes. By measurements of anatomical parts and camera-lucida drawings, an attempt has been made to compare these particular subgenera on a basis of gradual divergence of certain structures. For this purpose a series of tables was compiled in which apparently unstable structures were compared to a relatively stable figure in all available species of the selected subgenera.According to my findings, it was concluded that there is no strict correspondence between the major, intermediate, and minor castes of different subgenera of the genus Nasutitermes. Particular reference is made to the work of N. Holmgren ('12) and to that of J. S. Huxley on heterogonic growth.
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  • 24
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    Journal of Morphology 51 (1931), S. 195-205 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The branchial nerve of Mytilus edulis, traced by means of serial sections, has been found to be limited entirely to the epithelial and connective tissues bordering the axis of the gills. Most of the numerous branches which originate from the branchial nerve extend posteriorly and lie close to the interfibrillar matrix of the connective tissue which supports the epithelium of this region. Fibers of these nerves have been traced to this epithelium.The chitinous supporting structures of the gills lie in close proximity to these nerves, yet neither nerves nor nerve fibers have been observed to penetrate them. Moreover, a careful study of the gill tissues fails to reveal the presence of structures which might be interpreted as nerves or nerve fibers.Since no innervation of the gills has been demonstrated, it seems probable that the ciliary activity of the gill epithelium is not regulated by means of fibers connected with the central nervous system.
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  • 25
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    Journal of Morphology 51 (1931), S. 291-307 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spironympha is discussed as valid genus. It was described by Koidzumi ('16); later it was redescribed by the same author as Microspironympha ('21). Therefore, according to the rules of nomenclature, it is Spironympha.The genus is compared with the related genera: Spirotrichonympha, Holomastigotes, and Microjoenia.Spironympha is characterized by four flagellar bands which are spirally wound around the anterior part of the body; these bands occur only in the anterior end, whereas in Spirotrichonympha they extend almost to the posterior end. The parabasals are few in number, and they are attached to the basal granules of the flagellar bands; the anterior end is clear and almost free from cytoplasmic granules; and there are twenty to thirty anterior flagella which are attached to the base of the centroblepharoplast or to the basal granules of the flagellar bands. An axostyle is present.No centrosome occurs within the nucleus, but the centroblepharoplast has this kinetic function.Spironympha ovalis is described as a new species. It is ovoid; the average size is 38 μ to 44 μ. An axostyle is present. The host is Reticulitermes hesperus Banks.
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  • 26
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    Journal of Morphology 51 (1931), S. 1-117 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Four functional types of viviparity are recognized, and the last, pseudoplacento viviparity, is illustrated by a review of the embryogeny of a species of Polyctenidae. This insect normally has ten embryos in the reproductive tract in successive stages of development. The problem of fertilization is discussed, for there seems to be no spermatheca and spermatic clumps are present in the haemocoel. No organ of Berlese can be found. One, apparently a nymph, when sectioned revealed spermatozoa in even greater abundance than the mature females. Four to six of her offspring would seem to be paedogenetic.Females liberate ova that are yolk-free, and no chorion is secreted about them. Blastomeres are distinct, the embryonic envelopes are formed as usual, and hemipteran embryology occurs. The trophserosa functions until blastokinesis takes place, when the pleuropodial extensions evaginate and encompass the embryo which now lies in a pleuropodial cavity. The pleuropodia function as Lutrient organs, or psedoplacenta, until shortly before birth. At birth the embryo is a little more than one-third the adult body length and bears strongly developed setae.
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  • 27
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A morphologic study of the labyrinth, especially on the perilymphatic space with its physiologic aspect, is presented in this paper. The perilymphatic space starts its development with the chondrification of the auditory capsule, and is completed by the end of the first third of metamorphosis. The author divides the whole spatium into two parts: the ductus perilymphaticus et diverticula and the pars spongiosa spati perilymphatici. The ductus perilymphaticus et diverticula may play an important rǒle in carrying out the functions of both equilibrium and audition. The pars spongiosa serves not only to fasten the membranous labyrinth to the capsular wall, but acts as a safeguard for the functions of both the membranous labyrinth and the ductus perilymphaticus et diverticula. The ductus system may have more important physiologic relations than does the membranous labyrinth in connection with the cranial cavity and spinal cord, as to the change of pressure, the transmission of vibrations, the osmosis of fluids, etc. A number of microscopic and schematic figures are shown with reference to the anatomic and morphologic relations of the membranous labyrinth, auditory capsule, and spatium perilymphaticum.
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  • 28
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    Journal of Morphology 51 (1931), S. 309-318 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This investigation was made to demonstrate the direction of the current of a perfusing fluid (hence that of blood in nature) inside the so-called [renal-portal] vein of birds and to determine if this vein has any fine capillaries in the kidney substance. A domesticated male duck was anaesthetized with ether, and a warm saline (mixed with a little urea and urine) was passed through the aorta. The [renal-portal] vein was also perfused with the same fluid through the left internal iliac vein. At first the kidneys actively secreted semisolid urine, but gradually the strength of the latter varied from a milky to a watery fluid.Later, a warm carmine solution was perfused through the left internal iliac vein, and the path of the dye could be easily traced along the whole length of the left renal afferent (left [renal-portal] vein) and its final exit through the postcaval vein. The posterior lobe of the left kidney was partially tinged with red, probably due to diffusion, since the kidney substance should have taken a uniform red hue if there was any definite capillary system. The coccygeomesenteric vein contained no dye.These results (coupled with actual caliber measurements of the two [renal-portal] veins in duck and pigeon examined, the calibers of these veins increasing gradually posteroanteriorly) indicate that: 1) blood flows anteriorly in the [renal-portal] vein; 2) this vein does not break up into capillaries in the kidney substance, but receives larger affluent veins; 3) there is no [renal-portal] system in birds; 4) the urine secreted by birds is always semisolid.
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  • 29
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    Journal of Morphology 51 (1931), S. 467-525 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The general morphological and histological evidence accumulated by this study suggests the following facts: 1Under out-of-door conditions, in the vicinity of Philadelphia, Pennsylvania, embryonic development begins at deposition and continues to the middle or late spring, when hatching occurs. The postembryonic development is completed during the summer. Copulation and oviposition occur in the late summer and early fall.2The embryonic development may be divided as follows: aThe prerevolution period, in which the rudiments of organs and systems are formed.bThe early-revolution period, during which the direction of the embryo in the egg is reversed.cThe late-revolation period, or time of yolk circumcrescence and completion of the dorsal wall of the embryo.dThe postrevolution period. comprising development from yolk engulfment to hatching.3The sexes are differentiated during the early- and late-revolution periods.4In the differentiation of the genital rudiments, a) the germ cells are segregated into groups; b) and indifferent mesodermal element grows in among the germ cells of such a group; c) the processes of this cell (the apical cell) form intimate connections with the processes of connective-tissue elements surrounding the germ-cell group; and, d) the covering membrane of the genital rudiment grows in between the various germ-connective-tissue cell groups, completing the rudiment of the follicle.5When the adult condition is reached the testis is functionally differentiated.
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  • 30
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    Journal of Morphology 51 (1931), S. 527-543 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A vacuome (‘Golgi apparatus’) consisting of small globular inclusions has been demonstrated in Chlamydomonas sp. These inclusions may be seen in the living, unstained organism; they are stainable vitally with neutral red; they have been stained vitally with neutral red and then blackened with osmic vapor under direct observation, and they have been impregnated by osmic and silver methods without previous treatment with neutral red.The reaction of these inclusions to the iodin test for starch suggests that they may play some rǒle, possibly one of storage, in the cycle of starch metabolism.
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  • 31
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    Notes: The segregation of the germ cells is related in time and differentiation to the ectoderm (ventral plate), the inner germ-band layer (lower layer) and the mesenteron (entoderm) rudiments. The inner germ-band layer is formed by invagination of cells from a median blastoporic groove and by cellular proliferations among the invaginating cells and from the median line of the ectoderm immediately caudad of the blastoporic groove. The mesenteron material is derived from inner germ-band layer material associated with the internal ends of the stomodaeum and proctodaeum. The germ cells are segregated from the lateral margins of the abdominal lobe ectoderm in the region of the amnion attachment as segmentation of the abdominal lobe is initiated. They ultimately become separated from the ectoderm cells of the lateral wall and from the amnion and migrate in a passive manner onto the coelomic sacs where they become associated with the inner walls of the sacs. When the coelomic sacs unite the germ cells and the splanchnic wall mesoderm cells form two continuous cell strands from the first to the eighth abdominal segments, inclusive. These strands form the indifferent genital rudiments. An endeavor is made to correlate the segregation of the germ cells in the grasshopper with that of various other insects.
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  • 32
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    Journal of Morphology 56 (1934) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 33
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    Journal of Morphology 56 (1934), S. 21-49 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The literature relating to the flexor and adductor muscles of the thigh and their nerve supplies, in Sphenodon, the lizards, crocodiles and mammals was correlated and new dissections made of animals belonging to the last three groups. All of these muscles can be traced as individual entities from animal to animal without loss or addition to their number, although splitting may occur. The attachments of the muscles and their relationships to one another and to the two heads of the gastrocnemius are the same in all the reptiles studied. In the mammals one group, including the adductor longus and magnus and the retractor femoralis, has migrated from the tibia between the two heads of the gastrocnemius onto the femur, and another from the ilium onto the vertebrae, the one migration being caused by expansion of the gastrocnemius, and the other by expansion of the gluteal muscles. A new lateral flexor mass has been formed from part of the reptilian ilio tibialis by migration down the fibula. The nerve supplies of the various muscles are not constant when traced from group to group, and it is suggested that a muscle receives its nerve supply from the nerve nearest to it in embryonic development, so that when a muscle has migrated the nerve supply is no longer a reliable guide to its homology.
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  • 34
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    Notes: Histological studies of testes of both immature and mature individuals show that the peritoneal epithelium does not give up its proliferative capacities with the completion of testis differentiation. Certain regions of the antimesorchial surface retain their activity and continue to contribute cellular elements during testis growth. Stromal cells, germ cells, and sections of or entire seminiferous tubules originate from the peritoneum in the form of cord-like ingrowths. In this form, the proliferations of the germinal epithelium of the testes are similar to and homologous with the continuous proliferations of the germinal epithelium of the ovary.In Sternotherus, both testis and ovary differentiate out of a bisexual primordium in which the deeper parts of the germinal epithelium form an ovarian cortex. Since the germinal epithelium persists as an active part of both ovary and testis, it must be responsive to the same physiological factors of female or male differentiation respectively. It is indifferent sexually and once the direction of sex differentiation is established, the response of the germinal epithelium is in the determined direction. Its activity is then to produce either seminiferous tubules or ovarian follicles, and is directly dependent upon the processes of embryonic sex differentiation and determination.
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  • 35
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    Journal of Morphology 56 (1934), S. 295-323 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The primordia of the thymus bodies in Necturus begin to form in 7-mm. embryos. These structures arise as clumps of entodermal cells on the posterior dorsal portion of the first four visceral pouches; the first or last pouch, being rudimentary, fails to form such a primordium. All except the first of these primordia lose their connection with their respective pouches in the 16-mm. stage and lie free in the surrounding connective tissue. The primordium on the first pouch begins to show degenerative changes during that stage, losing connection with its pouch in the 23-mm. stage, finally to disappear altogether in 30-mm. specimens.The three remaining bodies continue to grow, but the second and third outstrip the fourth in development and begin to form Hassall's corpuscles in 32- to 34-mm. stages. Sections of 30-mm. Necturi show a few of these corpuscles fairly well developed and containing a faintly staining secretion. The fourth body remains relatively small a long time, not showing the Hassallian cysts until the animal is 60 mm. long. By shifting of positions and increasing in size, the three bodies come to lie in proximity, one behind the other, to form the definitive thymus gland of the adult. The gland lies embedded in the heavy musculature on top of the head in front of the gills.
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  • 36
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    Journal of Morphology 56 (1934), S. 339-359 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of vitamin E deficiency in the fowl were observed in Rhode Island Red males over a period of approximately 2 years.Mating experiments showed that after 1 year on the E-free diet all of the males were capable of fertilizing ova, but that after 2 years some of the males were sterile.Sperm smears showed that shortly after the beginning of the experiment, many of the mature spermatozoa exhibited an abnormal condition of the nuclear material of the head, while others remained normal.In histological sections of the testes made at the end of the 2 years, conditions varied from almost normal to complete atrophy, the latter being a condition that has already been described in the male mammal. Moreover, the conditions in any given section were not uniform for even in an advanced stage of E deficiency there were small islands of apparently normal tissue. However, in this case, as in the mammal, the process of degeneration affects the mature sperm cells first and gradually works to the outside of the seminiferous tubule thus attacking the youngest maturation stages last.The results of the experiment point definitely to destruction of the testis under prolonged E-deficient conditions but it is also quite apparent that the testis of the fowl is extremely resistant to vitamin E deficiency.
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  • 37
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper is an attempt to clear up the confusion concerning the osteological relationships among the Haplomous fishes.The osteology of Novumbra hubbsi was worked out by the dissection of numerous specimens. The various skeletal features found were compared with the osteology of Umbra limi, U. pygmaea, U. crameri, and Dallia pectoralis.A description of each skeletal element of Novumbra was made, followed by a description of the chief differences between it and the same structures in Umbra and in Dallia. No constant osteological differences were found between Umbra limi and U. pygmaea, and very few between these two species and Umbra crameri. Novumbra and Umbra have more in common with each other than either does with Dallia or Esox. The presence of postorbitals, postcranials, and the shape of the secondary shoulder girdle in Novumbra show it to be also closely related to Dallia and Esox.The relationships of the various forms are summarized in a synoptic key which lists the following groups: Order Haplomi. Superfamily I, Dallioidea; Family Dallidae; Genus and species, Dallia pectoralis. Superfamily II, Umbroidea; Family 1, Umbridae; Genus and species, Umbra limi, U. pygmaea and U. crameri; Family 2, Novumbridae; Genus and species, Novumbra hubbsi. Superfamily III, Esocoidea; Family Esocidae; Genus, Esox.
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  • 38
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    Journal of Morphology 56 (1934), S. 445-475 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper deals with the morphology of all the so-called gustatory and olfactory organs of blowflies, and describes tests conducted to determine whether these insects taste with their tarsi and smell with their antennae and palpi. Antennae bear two types of so-called olfactory hairs, while palpi bear only one. With the aid of an olfactometer it has been shown that antennae and palpi do not bear the olfactory organs.In order to explain the proboscis response, described by Minnich, it is not necessary to assume that tarsi bear gustatory organs, because: (1) a tarus bears no sense organs, except nine olfactory pores; (2) it is almost impossible to wet the tarsi with water or sugar water; and (3) when flies were in the proper nutritive condition and liquids were about 3 mm. from the tarsi, the insects were induced by a special method to exhibit the proboscis response. It was further clearly demonstrated by a similar method that tarsi can easily distinguish between chemically pure saccharose water and distilled water when these liquids are about 3 mm. from the tarsi. The responses, obtained by any method, are caused by two stimuli, one mechanical and the other olfactory. The act of touching the feet produces the initial stimulus and brings the liquids almost in contact with the olfactory pores on the tarsi.
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  • 39
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    Journal of Morphology 56 (1934), S. 513-531 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A study of the male reproductive organs of a hemipteron, Leptocoris trivittatus, has been made. The genital system, which consists of fan-shaped testes; the vasa deferentia, to which a single pair of accessory glands are attached; ejaculatory ducts and the copulatory apparatus, is described and photomicrographs of consecutive parts presented.Then an analysis of the method of aggregation and turning of the sperms is made by means of intravitam technic. Aggregation and turning commence in the early spermatid stage. A spherical cyst forms, the tails first grow centripetally and then push out toward the lower end of the cyst. This line of growth in the cyst moves the head ends of the spermatids to the upper end where aggregation gradually takes place.The cysts spiral up and across the follicles, the moving force being, probably, the elongating tails. Later they spiral down the follicle, development progressing rapidly. The descending bundles are mature sperm, held together by a cytoplasmic cap.The accessory gland secretes a milky substance which probably activates the sperm at a later stage. Peristalsis occurs in the wall of the gland and duct.The process of massing sperm into bundles before copulation insures effective translocation. Then peristalsis and movement of tubular fluids carry the sperm down the duct to the copulatory apparatus.
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  • 40
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    Notes: Homologous chromosomes entering parasynapsis are already split. This split evidently originates in each chromosome in the resting period prior to the last spermatogonial division. In the prophase of this division the daughter chromonemata in each halfchromosome were probably incompletely separated, but the succeeding telophase effects the completion of their separation. These processes are accompanied and suceeded by an elongation, straightening, and general paralleling of the split threads and by an elongation of the cell and its nuclear space.Parasynapsis begins with intimate approximation of the daughter threads in each homologue and is continued by approximation of the homologues at the usual [bouquet] and [zygotene] periods. There results the [diplotene] thread, which therefore consists of four completely distinct strands, but which exhibits a [two-strand] appearance due to parasynapsis between daughter chromonemata being further advanced than that between homologues.The pairing process begins at the distal ends and proceeds proximally. With parasynapsis complete, the nucleus enters the [diffuse] stage On emergence, disjunction is seen to have progressed from the distal ends to near the proximal ends in each pair and the [tetrads] have taken form. In the prephase that follows each strand in a tetrad may [crimp] independently, and with the condensation and matrix (?) formation that accompany it there results the spermatocyte ‘tetrad.’
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  • 41
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    Journal of Morphology 51 (1931) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 42
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    Journal of Morphology 51 (1931), S. 373-433 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An investigation into the number of chromosomes in thirty-seven species of Aphidiae belonging to twenty-seven geaera has shown that there is but one sex chromosome in the male cells of all but one species of Aphididae. That exceptional species is Euceraphis betulae Koch.The number of chromosomes and body characters are so closely correlated that we can safely judge the evolutional scale of any aphid by its number of chromosomes.In Aphididae the least number of chromosomes seems to be the most primitive.The number of chromosomes varies with the genera. The highest number is 1811 + X = 37 chromosomes, the lowest being 211 + X = 5 (diploid in male).The increase in the number of chromosomes seems to have been brought about by transverse divisions of the primitive chromosomes.The genus Tuberolachnus with 311 + X = 4 elements (♂) represents altogether different chromosomes characters from the genus Pterochlorus with 8 elements.In the genera Periphyllus and Calaphis there are species with a small m-element which is bivalent.
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    Journal of Morphology 52 (1931), S. 47-89 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In an investigation of the hatchability of eggs from hens fed on a diet deficient in vitamin E Card found that all embryos from these eggs died during development. Study of these chicks showed that a variety of conditions were responsible for death:During early development the rate of growth and differentiation was definitely slower than under normal conditions, but malformations were rare. Some embryos died during the first two days, due to disintegration of the circulatory system or its failure to become established. At the end of the fourth day there was a definite critical period which few specimens survived and by this time distinet pathological conditions had arisen in extra-embryonic structures. These involved wiping out of the vitelline circulation by establishment of a lethal ring in the blastoderm. This structure was produced by intensive cell proliferation in the mesoderm which resulted in choking out vitelline blood vessels and their subsequent degeneration. It also caused obliteration of the exocoele, with consequent failure of the allantois to expand. In addition, many embryos showed profuse haemorrage into the exocoele. The source of bleeding was most frequently in the atrium of the heart, and at the actual rupture peculiar cells occurred which were probably histiocytic mesenchyme cells.Although death was due directly to causes enumerated above, the ultimate responsibility rests upon conditions set up by them, namely: starvation, asphyxiation, and loss of the medium (blood) by which to carry on metabolic exchange.
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  • 44
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    Journal of Morphology 51 (1931), S. 435-465 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In some insects the selection of individuals which recover in equal periods of time from immersion in water may be used to obtain material of approximately uniform physiological state; Drosophila melanogaster, Meigen, was found to have a mean of recovery for the males 0.97 ± 0.542 minute later than the females, which would indicate a lower metabolic rate for the males. The Japanese beetle, Popillia japonica Newm., was found to have a mean of recovery from immersion in water of both sexes the same in August, while in September the males were retarded by 8.1 as compared with females. This would indicate that the males have and equal me abolic rate in August with the females and a lower rate in September. Carbon dioxide, hydrogen, and nitrogen produce in the flies a condition of asphyxiation similar to immersion in water. [Vestigial] flies recover from immersion in water in a fashion similar to ‘wild’ flies.The recovery periods from immersion in water in the flies can be used to group individuals into those possessing approximately equal egg-laying capacities and to isolate spent individuals from others still capable of laying eggs. Yeast appears to be more of a stimulant to egg laying than it is to larval growth. Groups of flies which were fed yeast were found to average 71 per cent increase in egg laying over groups of flies that were not fed yeast. The O2 consumption of the groups of flies actively laying eggs, as contrasted with the groups which were not so active, was found in the former to be 32.9 per cent greater.
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    Journal of Morphology 52 (1931) 
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  • 46
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    Journal of Morphology 52 (1931), S. 91-113 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper discusses very briefly the ultraviolet microscope and the developments which have led to a successful technique for optically sectioning living cells; also the ultraviolet photomicrographs of living sperm cells of certain grasshoppers, which show clearly the spinning out of the chromonema from solid blocks of the diatene stage, the pairing of same in the leptotene stage, the development of the tetrads, the final distribution of the chromosomes in the resulting spermatids and their return to a spiral chromonema, each inclosed in its own vesicle. The details of the cytoplasm are equally well brought out.
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  • 47
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    Journal of Morphology 52 (1931), S. 165-194 
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Neutral-red staining in Daphnia, legume seeds, starfish eggs, and Palaemonetes shows reactions to temperature changes which may be correlated with the thermal reactions of enzymes.
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    Journal of Morphology 52 (1931) 
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  • 49
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The oldest parts of the fibrous, cartilaginous, and bony head skeleton of vertebrates descend from the amphioxid ancestors of the myxinoid fishes. The skeleton of the velum and jaw bars of the amphioxids transform into the jaw apparatus and hyoid-velar head skeleton of the myxinoids, and some parts are passed on by inheritance to the teleostome fishes (sturgeons). These anatomical characters prove descent with modification. The theory of the origin of jaws and hyoid from branchial cartilages is not supported by the facts, as both jaws and hyoid structures were developed long before branchial cartilages furnished material for head building. The Velata, the oldest of living vertebrates, include the amphioxids and marsipobranchs, and are marked off from the higher forms by the important organ, the velum, which separates the prebranchial from the branchial head. A remnant of the velum inherited by all of the higher vertebrates is the hyoid mechanism - an important anatomical landmark.
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  • 50
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    Journal of Morphology 52 (1931), S. 485-511 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This work was designed to determine the ontogenetic variability of the morphology of mitochondria of the hepatic cell.The mitochondria of the cells of the hepatic diverticulum are minute spheres. These spheres enlarge, become associated, forming beaded filaments, which in turn become smooth filaments, the process culminating in the twenty-day fetus. There is no individual or lobular variabillty in fetuses of a given length. One-half day before birth the above process is reversed, so that separate spheres are found in the eight- to twelve-hour young. This enlargement and enspherulation are accompanied by an accumulation of large quantities of glycogen. After this age, the spheres become associated into beaded filaments again and the glycogen disappears, the cycle ending at thirty-three hours. From two to eight days of age there is great individual variability.Mitochondrial morphology characterstic of the adult is first found in the fourteen-day young, when cells contain long, smooth or beaded filaments, rods, and spheres. There is no lobular variation as to types of mitochondria, but only in numbers, the cells around the central vein containing fewer mitochondria than other cells of the lobule. Variation between individuals after birth is due to something other than age, type of food, period of digestion, and length of starvation. Fat is formed within spherical chondriosomes.
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  • 51
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    Journal of Morphology 52 (1931), S. 525-533 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are twenty-seven spermatogonial chromosomes in Tenoder'a sinensis, three of which are larger than the others and lag behind in anaphase. These three chromosomes have been traced through the prophases of the first spermatocyte to the metaphase, where they appear as a hexad. In the first spermatocyte division two of the constituent diads of the hexad pass to one pole, the remaining one to the other, thus giving rise to two types of second spermatocytes, one with thirteen and the other with fourteen chromosomes. There are twenty-eight chromosomes in somatic metaphases of the female; four of these chromosomes are larger than the others. The sex chromosomes of the male are represented by the formula Xa + Y + Xb, that of the female by 2Xa + 2Xb.Similar conditions are reported for Mantis religiosa and Stagmomantis carolina.
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  • 52
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    Journal of Morphology 55 (1934), S. 421-433 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Paramecium caudatum was studied by micro-incineration, by stained control sections, by vital staining, and by osmic impregnation. It was found that a slow initial heating and a slow cooling after incineration greatly reduce the amount of distortion and shrinkage in the incinerated specimens. Most of the cytoplasmic components and organelles, including vacuome, chondriome, cilia, and basal granules, trichocysts, food vacuoles, and the nuclei, could be identified by their ash. No ash is found in the pellicle and only a small amount in the hyaloplasm. None of the osmiophilic components such as granules or the walls of the contractile vacuole could be identified in the incinerated specimens with certainty. The larger amount of ash in the endoplasm as compared with the ectoplasm is due to the large number of granules in the former region. The nucleus and some of the granules near the nucleus show traces of iron.
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  • 53
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When sexually mature Procotyla fluviatilis Leidy (commonly but erroneously known as Dendrocoelum lacteum) are cut transversely into head, pharyngeal, and tail pieces of about equal length, the head and pharyngeal pieces fail to regenerate in a large percentage of cases and tail pieces never regenerate. When regeneration occurs in head and pharyngeal pieces it is somewhat slower than in similar pieces of Planaria maculata Leidy and Planaria agilis Stringer with which comparisons were made. Cutting mature Procotyla into larger numbers of pieces usually results in death of all, although smaller pieces from prepharyngeal regions sometimes regenerate. Juvenile P. fluviatilis have greater powers of regeneration, as shown by cutting head and pharyngeal regions into greater numbers of pieces, but tail pieces do not regenerate. These observations confirm and extend those of earlier investigators. Such a restricted power of regeneration contrasts with well-known powers in P. maculata and P. agilis. Counts of formative cells, from which new parts arise in all three species and which are regarded by the authors as a persistent embryonic stock, indicate about 8.5 such cells in P. maculata to 1 in P. fluviatilis per unit area. It is concluded that regeneration in planarians is correlated with numbers of such formative cells and that histological factors are no less important than physiological ones. The paper is preliminary to a study of effects of x-rays upon regeneration.
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  • 54
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    Journal of Morphology 55 (1934), S. 435-475 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The centrioles are recognized early in the prophase of the primary spermatocyte. They soon become double and migrate around the nucleus in opposite directions. As this is completed the nuclear membrane breaks down and spindle fibers appear. The centrioles divide in the metaphase at a time when the centrosome is still perfectly spherical. The centrosome divides in the anaphase, giving the two centers for the second division. The centriole disappears in the spermatid and cannot be seen in later stages. The behavior of the centers during the spermatocyte divisions is strikingly like that of the egg centers and other types of mitoses. Therefore, it is concluded that the centrioles of the spermatocytes are not to be regarded as different from the centrioles in other types of mitoses.The Golgi bodies increase in number and size during the growth period of the cell. They are usually found in the shape of rings. From these rings are produced the refringent granules which fuse in the late spermatid to form those of the mature sperm. It is therefore concluded that this process represents the formation of the acrosome. The mitochondria show little change during the maturation divisions. In the late spermatid they aggregate around the nucleus and become vesiculated. This is interpreted as the formation of the prenebenkern.
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  • 55
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    Journal of Morphology 51 (1931), S. 613-618 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The onset of hibernation in Melanoplus differentialis eggs kept at high temperatures is accompanied by a fairly abrupt cessation of cell division. The total number of mitotic figures present in the different individuals of a series of embryos of this grasshopper, from eggs kept for eighteen to twenty days at 25°C. from the time of saying, was found to vary between 1000 and 4400. In contrast to the conditions found in eggs of this age, embryos from eggs kept twenty-seven days at 25°C., as well as those older and still in the hibernating state, contained few or no dividing cells. During the course of the work it was found that, in rare cases, hibernation failed to occur, a few or many of the eggs developed without a pause when kept at 25°C., and hatched at approximately the thirty-eighth day. The detection of variations in the rate of mitotic activity over short periods, as originally planned, was found impossible, because of the comparatively small number of embryos used.
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  • 56
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    Journal of Morphology 52 (1931), S. 155-164 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Some pathological effects of supersonic waves produced by the piezo-electric oscillator described by Wood and Loomis ('27) are described.Death of fish and frogs was due to haemolysis of erythrocytes within the gill capillaries. Disruption of gill filaments, trauma, and extravasation in the head and gill region and in the peripheral musculature were noted.No effect on the nervous system was apparent histologically.Organisms were not killed in water under hyper- or hyponormal pressures. In these cases no cavitation of gases took place.Isolated frog sartorius muscle in Ringer's was not damaged.Bubbles of gas were easily observed within the muscle cells of the tadpoles when such cells were not more violently disturbed. Such bubbles were abundant in the more fluid muscles of four- or five-day tadpoles, less abundant in 15- to 35-mm. Lebistes, and entirely lacking in adult frog sartorius. Protoplasmic viscosity differences probably explain the gradient.The above-observed intracellular cavitation explains the muscular destruction, the haemolysis, the change in specific gravity of organisms subjected to the wave treatment, and may offer light upon the stimulatory effect of such waves on excitable tissues (compare Harvey, '28).
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  • 57
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    Journal of Morphology 52 (1931), S. 195-215 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this paper evidence is given in support of the author's statements (Rees, '30) that in ciliates in the genus Diplodinium a neuromotor apparatus, as described and figured by Sharp ('14), could not be differentiated. For the study of minute anatomy ciliates were cut into serial sections 3 μ thick. The body which in D. medium appeared to correspond to the motorium of D. ecaudatum was shown to be a fold of the middle layer of ectoplasm. Fibers, described and figured by Sharp as connecting the motorium to the organelles of locomotion and of food taking and to a ring about the esophagus, could not be differentiated. Other fibers which Sharp designated as opercular were shown to be part of a fibrillar complex extending throughout the middle layer and the inner boundary layer of ectoplasm. The walls of the esophagus were shown to be formed by the fused middle and inner layers of the ectoplasm. The esophageal fibers therefore belong also to the above-mentioned fibrillar complex. In D. medium a system of esophageal membranelles was differentiated, described, and figured. The ciliary systems of Paramaecium ecaudatum and of Diplodinium medium were shown to be strikingly similar. The principle of descent from a common ancestor adequately explains the above similarity, but is out of harmony with the discrepancies between Sharp's account of D. ecaudatum and this account of D. medium.
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  • 58
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    Journal of Morphology 52 (1931), S. 249-275 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The flagella of the endodermal cells of hydra have their origin in the form of a cytoplasmic spherule which appears on the cell membrane just above the blepharoplast. This spherule moves outward, and in doing so forms a small cylinder, which, in time, flattens down into a ribbon-like flagellum, the edge of which is slightly thickened. Endodermal cells were found to bear from one to five of these flagella. Dissociated endodermal cells become amoeboid and are able to move about quite freely, taking up particles of food with pseudopods; these cells are also able to elaborate flagella. In the normal well-fed hydra the endodermal cells are found to fragment endogenously; these endogenous fragments pass to the tentacles and other outlying regions, where they are taken up by the endo-epithelio cells lining these regions. The endoderm is frequently thrown into villi of quite large size: these villi, when studied over a period of days, are found to deteriorate; the cells which composed them wander to the tentacles, buds, and basal regions by means of their flagella and amoeboid movement, where they deteriorate, the cell particles being taken up by the epithelio cells lining these areas.
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  • 59
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    Journal of Morphology 52 (1931), S. 277-307 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The most important conclusion of this investigation is that the vacuome and the classical Golgi apparatus are independent cell components in the oocytes of Ophiocephalus and Rita. The same conclusion has been arrived at by Nath in Rana tigrina. The vacuoles, the Golgi elements, and the mitochondria can be seen intra vitam side by side.In Ophiocephalus the vacuoles give rise to albuminous yolk, as has been rightly claimed by Hibbard for Discoglossus and by Hibbard and Parat for Perca and Pygosteus. The Golgi elements give rise to the fatty yolk as in so many other forms of oogenesis described by Nath and others.In Rita the fate of the vacuoles and the Golgi elements is unknown, as the fish suddenly disappeared from the Ravi during the spawning period.
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  • 60
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Between December 10th and January 24th, using red, green, and white electric lights at equal intensities of about 1.7 foot-candles, sixty-nine males, with females, were subjected nightly to, (a) constant six- and six-and-one-quarter-hour periods of illumination; (b) periods increasing gradually from one-quarter to six and one-quarter hours; (c) no added light (controls), in a basement room lighted by day from three large windows. Relative heat intensities reaching the birds were: for white, 1; for green, 2.5; for red, 10.Birds were killed for testis study at 5, 12, 16, 22, and 23 days.Refractory period was shorter, and modification of spermatogenic activity much greater, under a than under b types of treatment, as compared with controls. Effects were also more consistent.Descending order of testis activity induced at all stages was red, white, control, green, under both a and b.Effects on testis activity are not proportional to heat intensity of incident light, but depend on wave length, since green effect is not intermediate between those of white and red, as its heat intensity is. Green inhibited germ-cell activity even in birds already at normal midwinter minimal condition.Constant six-hour red-light treatments, of this intensity, induced flrst appearance of metamorphosing sperms in twenty-three days in midwinter.Apparatus and mode of light regulation and measurement are described.
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  • 61
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    Journal of Morphology 52 (1931), S. 535-563 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A study of cell division in the chick embryo has revealed in striated muscle and in the early stages of all the principal tissues and organs a process, followed by the greater percentage of the dividing nuclei, which resembles amitosis, but is undoubtedly a highly modified form of mitosis. This process is designated ‘modified mitosis’. The belief that this is essentially mitotic rests upon the fact that a number of discrete bodies may be distinguished in the one or two chromatin masses of each nucleus. These masses, or ‘mulberries’, might easily be mistaken for nucleoli or karyosomes were it not that they exhibit division by elongation and constriction. These structures probably represent masses of minute and closely clumped chromosomes in somatic number dividing in a qualitative and a quantitative fashion. As additional evidence there are present between the dividing mulberries exceedingly fine fibers which possibly represent an attempt at spindle fibers. Neither centrosomes nor asters are present, but since, if present, they would have to be of the intranuclear variety (the nuclear membrane never disintegrating) their absence is immaterial. The nucleus divides not by constriction, but by the formation of a nuclear plate. This process of modified mitosis is probably a device which favors the speed of nuclear proliferation necessary to such rapidly growing tissues.
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  • 62
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    Journal of Morphology 56 (1934), S. 621-635 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 63
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    Journal of Morphology 55 (1934) 
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  • 64
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    Journal of Morphology 52 (1931), S. 565-592 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Serial sections of seven embryos were examined, in four of which the chondrocrania were reconstructed. Parachordals appear as independent precartilages on each side of the notochord in the otic region. Later chondrification occurs, and they fuse with the notochord. Orbitals and trabeculae appear as independent precartilages; later, as cartilages they fuse with the basal plate and with each other, forming the cranial wall between the orbital cavity and brain. An apparent shifting posteriorly of the bases of the fifth, seventh, and eighth cranial nerves, in respect to the anterior end of the notochord and to the otic vesicles, occurs between the 10-mm. and the 60-mm. stages. The otic vesicles, proportionately small in the 10-mm. stage, reach their relatively largest size in the 19-mm. embryo. The floors of the otic capsules begin as lateral extensions of the basal plate at the 25-mm. stage, and from these anlagen chondrifications extend, forming the anterior and posuerior cupolas. Most of the tegmen cranii forms by chondrifications that approach the median plane from each side. It is practically complete in the 60-mm. embryo. The cervical neural arches also contribute in forming the tegmen cranii and the occipital region. The ventrally recurved end of the notochord of the 10-mm. stage persists through the 60-mm. embryo.
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  • 65
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    Journal of Morphology 56 (1934), S. 125-155 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The chromosomes of D. melanogaster have been followed through the entire cycle of mitosis in ganglion cells. Primary constrictions exist at about the middle of the second and third chromosomes, at a sub-median position in the Y, at a sub-terminal in the X, and probably also at a sub-terminal position in the fourth chromosome. Secondary constrictions, in addition to those reported by Bridges, are sub-terminal in the arms of the second and third chromosomes. A pronounced sub-median secondary constriction in the left limb of the second chromosome offers a criterion for distinguishing between the second and third chromosomes, and between right and left arms of the second chromosome. The proximal secondary constriction in the X-chromosome and that in the short arm of the Y are associated with the normal development of the nucleolus. Anaphase chromosomes are longitudinally double, the split following the turns of the chromonemata. Metaphase and anaphase chromosomes are essentially isodiametric from end to end, except at the constrictions or indentures. Somatic pairing of chromosomes reaches its maximum expression during late prophases, both in male and female ganglion cells. The four chromatids of the tightly appressed homologues open out in two planes giving distinct chiasma-like configurations. Separation of the paired chromosomes is completed in late prophase, so that at metaphase the homologous chromosomes are not in contact.
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  • 66
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    Notes: The cytology of corpora lutea of non-pregnant ewes is described with reference to the origin, structure, fate, and function of these organs. The lutein cells, characteristic of corpora lutea, are derived from the cells of the stratum granulosum of the Graafian follicle; connective-tissue cells, embryonic cells, and non-striated muscle cells, from the theca interna; and erythrocytes, leucocytes, and histiocytes, from the blood stream. The lutein cells undergo changes in size, nuclear structure, and cytoplasmic inclusions correlated with the period in the estrous cycle and disappear during retrogression. Although secretory products have not been identified, a secretory function is postulated on the basis of the structure of the cell.
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  • 67
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    Journal of Morphology 56 (1934), S. 231-241 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: The three species of Trichonympha found in Zootermopsis angusticollis were studied by micro-incineration, by control sections, and by Macallum's methods for iron and calcium. The mineral ash is concentrated in the neuromotor system, chromatin, nuclear membrane, the posterior end where ingestion takes place, and in cytoplasmic granules. Micro-incineration and Macallum's Prussian blue method reveal iron in the chromatin alone; Macallum's haematoxylin gives a positive test for iron in the chromatin, rostrum, neuromotor fibrils, etc. It probably is not as specific as the other methods. The two staining methods give negative tests for iron except after acid hydrolysis. Calcium is present in the chromatin, neuromotor system, posterior region of the body, and in many endoplasmic granules. The localization of calcium is correlated with the localization of normally gelated regions.
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  • 68
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    Journal of Morphology 56 (1934) 
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  • 69
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    Journal of Morphology 56 (1934), S. 213-229 
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    Notes: The conspicuous intracellular fibers (figures of Eberth) which are present in the basal epidermal cells of Rana pipiens and Rana clamitans tadpoles are thought to be connective tissue branches from the corium. They are not believed to represent fused mitochondria as concluded by Saguchi ('13). Their probable function is to furnish support to the basal epidermal cells and to strengthen the connection of the epithelial layer to the corium.It is believed that fully developed tadpole skin, before the period of metamorphosis has begun, consists of only two layers of cells, although there may appear to be more. Each of these layers is believed to be self-maintaining by mitotic division within the individual layer. The basal layer apparently does not furnish cells to the outer layer, nor was any evidence found that the outer layer is sloughed during the larval period.
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  • 70
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    Journal of Morphology 56 (1934), S. 267-293 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The results of recent investigations concerning caste determination among termites have been briefly reviewed with emphasis upon the work of Thompson ('17). From examination of new data upon the development of Reticulitermes arenincola Goellner, R. flavipes (Kollar), and R. tibialis Banks, and of Thompson's original R. flavipes material, I am unable to substantiate her claim that the sterile and reproductive castes are separable into two distinct groups at the time of hatching. I could distinguish them first in stadium three and suggest that the second stadium may be a critical period in differentiation. From evidence to date, it must be granted that both intrinsic and extrinsic factors may play a role in the production of castes. The delay in appearance of demonstrable caste differences until the third stadium in the genus Reticulitermes at least admits of an opportunity for extrinsic factors to be effective. Growth and metamorphosis of various structures which ultimately lead to the three differentiated castes have been followed through successive stadia. Gynandromorphs and intercastes among social insects give indication of the physiological and genetic factors influencing both morphological and behavior differences among castes.
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    Journal of Morphology 55 (1934), S. 565-565 
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  • 72
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    Journal of Morphology 56 (1934), S. 1-19 
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    Notes: The origin and development of the posterior cardinals and associated veins in relation to the swim bladder, as well as their morphology, have been studied in Lepidosteus. The posterior cardinals develop, beginning in the 4-mm. stage, as sinuses in the mesenchyme dorsal to the gut and near the mesonephori. A pneumatic vein appears first in the 13-mm. stage. It collects from the posterior portion of the swim bladder and empties into the right posterior cardinal. In the younger stages the caudal vein empties directly into the posterior cardinals as is the case in the adult cyclostome, but by the 58-mm. stage it has joined veins dorsal to the mesonephori forming a renal portal system. An anal vein appears in the region of the anus and joins the caudal. Later, with the development of the renal portal system, the anal separates from the caudal to become the single posterior extension of the posterior cardinals. The posterior portion of the right cardinal contributes largely to the development of an abdominal portal vein extending from the posterior root of the right posterior cardinal to the liver. These relationships of the posterior cardinals differ from those found in other fishes, due perhaps to the function of the right cardinal and its pneumatic branch in collecting blood from the swim bladder.
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    Journal of Morphology 56 (1934), S. 101-123 
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chemical analyses of the lipoids in fresh and autolyzed pancreas of the cat have been correlated with the staining reactions of sections of this organ preserved by three cytological methods. Quantities of total fats and of phospholipins, the iodine numbers of total fats and of phospholipins, and the free fatty acid numbers were determined. None of the methods of fixation used reveals the total fat content of the tissue. The intensity of staining of material fixed by Helly's method and stained with acid fuchsin is dependent on the phospholipins of the tissue, but the exact nature of the relationship is not certain. The intensity of staining of material preserved by Champy's method and stained with acid fuchsin can be correlated with the iodine number of the phospholipins of the cells. The degree of blackness of sections preserved by the Kolatchev-Nassonov method can be correlated with the iodine number of the phospholipins of the cells. The free fatty acid content is probably also a significant factor. The methods demonstrate lipoids qualitatively rather than quantitatively. Only physiologically similar cells may justifiably be compared by the cytological methods studied.
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    Journal of Morphology 56 (1934), S. 157-179 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two features of this study have furnished direct evidence for the material continuity and individuality of the chromosomes in the epithelial cells of the larvae of Ambystoma tigrinum (1) the tracing of the complete history of a specific chromosome, the nucleolus-containing chromosome, throughout the successive stages of mitosis and interkinesis, (2) the following of the exact parallelism in behavior (during mitosis) of the chromosomes in a given nuclear group with that in a single chromosome which has been isolated in the cytoplasm from the main chromosomal complex.Each of the two nucleoli is subterminally located in the short arm of one of two particular V-shaped chromosomes. The latter are probably homologues.78: In this subterminal chromosomal position the nucleolus exhibits in fixed and stained preparations an achromatic character in late prophase, metaphase, anaphase and early telophase, while it presents itself as a chromatic element in middle telophase, late telophase, interkinesis and early prophase.The nucleolus is not a simple homogeneous body, but rather a complex structure, the nature of which is revealed in the study of its evolution during the chromatic phase of its cycle in mitosis.
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  • 75
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    Journal of Morphology 56 (1934), S. 203-212 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The skull, mandible, and five pairs of long bones from the skeletons of 125 muskrats were weighed and measured. Each bone of the pairs of long bones was weighed and measured separately. Thirteen dimensions of the skull were determined.The long bones are slightly less variable in length than the skull dimensions. There is a rather wide range of variation in the thirteen dimensions of the skull, with the length and breadth of the skull less variable than the lengths of the long bones.The coefficients of correlation show that the weight of the skull is a good index to the weights of the long bones. The skull length has likewise high correlations with the lengths of the long bones and the longitudinal dimensions of the skull, with the exception of the palatine slits. The transverse diameters are not significantly correlated with the skull length.The long bones are asymmetrical in weight and length. They are longer more frequently on the left side and all except the tibia are heavier more frequently on the left side.
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    Journal of Morphology 56 (1934), S. 243-265 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The position of the inner ear and its relation to surrounding structures in the fetal head is ascertained. The growth and shape change of the cochlea is followed and measured. The change in size and appearance of the ductus cochlearis has been followed througout the various fetal stages. The growth and development of the scala vestibuli and scala tympani have been noted. The size and shape of the cells of the organs of Corti and the development and attachments of the tectorial membrane have been measured. The growth and developmental relationships of the tunnel of Corti have been followed. The growth and time of appearance of the organs with their relationship to hearing have been treated. The type of cell structure and the various structural changes throughout the development have been noted and correlated with the growth and size of the structure as a whole. The repidity of growth of all separate parts has been correlated and united to show the extent of development of the newborn rat inner ear.
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    Journal of Morphology 56 (1934), S. 361-369 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The diploid number of chromosomes of a species of Indian earwigs, Labidura riparia, is fourteen; six pairs of autosomes with X and Y idiochromosomes for the male; six pairs of autosomes with X and X for the female.The chromosome distribution is normal, and constant for all the individuals studied.X and Y are derived from a single chromatin nucleolus of the early growth period which assumes a clavate form later, and remains in the same form till the metaphase of the primary spermatocyte is reached.
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  • 78
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    Journal of Morphology 56 (1934) 
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  • 79
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    Topics: Biology , Medicine
    Notes: During spermatogonial stages in Xiphophorus and Platypoecilus maculatus and Platypoecilus couchiana and in the hybrid, two distinct types of cells are observed, a large lightly staining primary spermatogonium and a smaller deeply staining secondary spermatogonium. Chromosomes of primary spermatogonia of Platypoecilus maculatus and Platypoecilus couchiana differ somewhat from those of Xiphophorus helleri and Xiphophorus jalapa, but are very similar to those of the hybrid at this stage.Chromosomes of Xiphophorus at this stage are long and thin, while those of Platypoecilus and of the hybrid are somewhat short and thick. Visible chromosome differences appear only during the primary spermatogonial stages.The haploid group of chromosomes, numbering twenty-four in the hybrid, so resembles that of Xiphophorus and of these two species of Platypoecilus in both number and morphological characteristics during the primary spermatocyte division as to be practically indistinguishable from either. Persistent lagging of one large chromosome as it comes upon the equatorial plate during the primary spermatocyte division is very noticeable. Precocious division of this chromosome and the advancing of its two daughter components to the poles of the spindle in advance of other chromosomes indicates that this chromosome may be a sex chromosome. The fact that two daughter components are identical morphologically and that each secondary spermatocyte receives one of them suggests that the male in Xiphophorus and in Platypoecilus is homogametic.
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    Journal of Morphology 56 (1934), S. 577-591 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nuclear band of the cells of the salivary glands of Chironomus larvae regularly consists of four segments or chromosomes. Each of these may be recognized by its characteristic distribution of chromatin discs of various sizes. When nucleolar elements are present they have a definite location in relation to the chromation discs of a certain chromosome. The diploid number of chromosomes is eight; therefore, the four segments in the cells of the salivary glands represent four pairs of homologous chromosomes in somatic synapsis which here is not a simple approximation but an accurate pairing part by part of the homologous chromosomes.
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    Journal of Morphology 56 (1934), S. 593-601 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The rate of maturation and of development during the first 4 days has been followed in Melanoplus differentialis eggs (from mated females) collected (1) just before they were laid, or (2) immediately after oviposition had been completed and (1) either fixed at once, or (2) after incubation at 25°C. for definite periods.
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    Journal of Morphology 56 (1934), S. 603-619 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Maturation and early cleavage in unfertilized Melanoplus differentialis eggs have been followed with material secured immediately before as well as after oviposition, and (1) fixed at once, or (2) held in an incubator at 25°C. and, subsequently, fixed at selected intervals. Eggs ready to be laid were all found in the metaphase of the first maturation division. The second polar body is given off (at 25°C.) within 5 to 7 hours after laying. Meiosis appears to be unaffected by the absence of the sperm nucleus and proceeds at the same rate as in fertilized eggs. No morphological differences could be found between the process here and in eggs from mated females.During early cleavage, or later, the diploid number of chromosomes may be restored in some (or perhaps all) cells of the embryo.Development begins in the greater number of these unfertilized eggs but is successfully completed in only a very few.
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    Journal of Cellular and Comparative Physiology 4 (1934) 
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    Journal of Cellular and Comparative Physiology 4 (1934), S. 283-296 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Cellular and Comparative Physiology 5 (1934), S. 229-247 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Cellular and Comparative Physiology 5 (1934), S. 347-358 
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    Journal of Cellular and Comparative Physiology 5 (1934), S. 399-413 
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    Journal of Cellular and Comparative Physiology 5 (1934), S. 151-169 
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    Journal of Cellular and Comparative Physiology 4 (1934), S. 185-209 
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    Journal of Cellular and Comparative Physiology 4 (1934), S. 297-312 
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    Journal of Cellular and Comparative Physiology 4 (1934), S. 475-482 
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    Journal of Cellular and Comparative Physiology 4 (1934), S. 527-544 
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    Journal of Cellular and Comparative Physiology 5 (1934), S. 53-72 
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    Journal of Cellular and Comparative Physiology 5 (1934), S. 219-228 
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