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  • Cell & Developmental Biology  (172)
  • Seismology  (34)
  • 1925-1929  (206)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 345-369 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The specimen described presents a typical intersexual condition, in which not only the primary sex characters, but also the accessory sex organs and the secondary sex characters are of a mixed type. Both gonads are ovotestes, in which the ovarian as well as the testicular tissues are morphologically normal, but functionally underdeveloped. Stromal hyperplasia is distinct, especially so in the left gonad; it is probably a functional factor in the generative process of the spermatic tissue.Sex transformation in the intersexual frogs may probably be initiated by an abnormality in sex differentiation or in the genetical constitution of sex, and is only subsequently influenced and modified by environmental action. Absolute dominancy of male sex in the process of sex transformation is questionable. There are indications that in frogs sex transformation may possibly occur in a female direction.
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  • 2
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Maturation of the male germ cells in the rat shows some slight modifications of the typical procedure in sex cells, a distinct and rather prolonged synapsis occurring before synizesis and a confused stage immediately after it. The clumping in synizesis is not extreme. In the mixed strain of rats both twenty-one and thirty-one tetrads appear in the late diakinesis. This procedure in the male resembles the maturation of the oocytes in only two points, the beginning of the process, the deutobroch nuclei, and the end of it when the haploid number of chromosomes take their places on the spindle.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 493-541 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cells of the blastoderm which are to form the serosa are two- to four-nucleate; the smaller cells of the embryonic rudiment, uninucleate. The band-like embryonic rudiment encircles the yolk at the equator of the egg. The amnion does not begin to form until after the serosa completely covers embryo and yolk. The epithelium of the midgut arises from cells situated at the tips of stomodaeum and proctodaeum. These cells, though not differentiated from adjacent ectoderm at the time of the invagination, are nevertheless interpreted as part of the preprimordium of the endoderm. In the eighty-four-hour stage a fold of amnion grows over the dorsal side of the embryo, entirely covering it in the course of the next few hours. A portion of the amnion thus forms the dorsal wall of the embryo. At the completion of the amnion the embryo rotates so that its ventral side is directed toward the egg center. The amnion raptures just before the larva begins to feed on the yolk which still remains around it. The serosa is consumed before hatching, which takes place about five and one-half days after deposition.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 585-609 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The caeca of fourteen bantam fowls have been studied. These fowls ranged in age from six days' incubation to three years after hatching. Between the fifth and sixth days of incubation rectal caeca arise as evaginations from the intestine at the junction of the ileum with the colon. The develoing caeca closely resemble histologically the intestine to which they are attached.The caeca are essentially devoid of content until about the nineteenth day of incubation, but during the remaining days of incubation are gorged with a bluish-gray material similar to that found in the colon. Thus, an early defecatory function is indicated.In general, the proximal third of the caeca remains histologically similar to the intestine, but the distal two-thirds undergoes regression. The latter involves the atrophy of the epithelium and glands, accompanied by the appearance of lymphoid tissue. Much of the lymphoid tissue eventually disappears, to a large extent by atrophy and dissolution of the leukocytes. However, to some extent, lymphocytes develop into granulocytes which escape with other leukocytes into the lumina of the caeca and there disintegrate.Lymph nodules begin to appear in the caeca about one week after the chick hatches. The leukocytes, at least in part, arise in situ from the reticular stroma. Eosinophils arise in certain areas of the tunica propria, and in the earlier stages of their development resemble large lymphocytes, in the cytoplasm of which basophilic, amphophilic, and acidophilic granules are intermingled.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 135-199 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Definite information concerning the time of development and location of the different imaginal discs of Drosophila melanogaster was needed in order to interpret especially the gynandromorphs, mosaics, and intersexes that have been extensively reported in cultures of this fly. This information was also desirable for many of the mutant types. It was not known, for example, when an organ was reduced or absent, whether its imaginal disc showed a corresponding reduction, or whether it was full size in the larvae and pupae, and failed to carry through to the later stages.Three mutant types with eyes smaller than those of the wild type, namely, lozenge, bar, and eyeless, were examined. It was found that there is a corresponding difference in size as far back as the imaginal disc could be detected. Similarly for the two mutants, vestigial and no-wing. Conversely for the mutant, bithorax, in which the metathorax is larger than the normal and has assumed many of the characters of the normal mesothorax, the imaginal disc was correspondingly enlarged.It follows that the effects of the mutant genes for these characters can be observed in the very earliest condition of the imaginal disc.
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  • 6
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 89-133 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the telophases each chromosome becomes inclosed in an individual sac or vesicle which, together with its contents, is called a chromosomal vesicle. The vesicular membrane is of cytoplasmic origin, but is formed under the influence of the chromosome and a droplet of karyolymph. A precise numerical correspondence between chromosomes and chromosomal vesicles has not been established, but it is evidence that most, if not all, of the chromosomal vesicles retain their individuality during the resting stage and until after the new chromosomes have been fully formed.The transformation of the telophase chromosome into the reticulum of the resting stage and the manner in which a new chromosome is formed from a portion of this reticulum are described in detail. In the early prophases each developing chromosome is embedded in a sheath or matrix of less deeply basophilic material, which disappears before the middle prophase is reached.The formation of chromosomal vesicles is interpreted as a device for doing more rapidly and effectively, under stress of special circumstances, the work that the nucleus must accomplish during the so-called resting stage.
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  • 7
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 201-225 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are eleven pairs of chromosomes in the somatic cells of the opossum.The sex chromosomes are of the x-x type in the female and the x-y type in the male.The number and type of the chromosomes are constant in the wide variety of tissues and organs studied, except that one dividing giant cell of the spleen showed an 8n number of chromosomes.The arrangement of the chromosomes in equatorial plates is that of an autosomal ring surrounding the centrally located sex chromosomes.
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  • 8
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In sections the protoplasm of the spinning gland of Platyphylax designatus Walker appears to be a syncytium with large, branching nuclei, which contain both nucleoli and chromatin granules embedded in a delicate linin reticulum.In the normal gland the nucleus is sharply marked off by a nuclear membrane from the granular, homogeneous cytoplasm. The Golgi apparatus appears as rings, loops, or comma-like structures, evenly distributed and without orientation to the nucleus or lumen of the gland.The nucleoli first increase both in number and size within the nucleus, then migrate out into the cytoplasm, where they undergo further growth, and finally are dissolved and passed out into the lumen of the gland as liquid secretion.Small vacuoles appear near the periphery of the gland in early periods of activity.In glands active for forty-eight hours all stages of the secretory process may be seen.In glands active for longer periods only vacuoles are present which we interpret as the remains of the secretory inclusions. There is a progressive decrease in the nuclear content of the nucleus.Throughout the activity of the gland the Golgi apparatus changes little from the normal condition, both in form and distribution. As activity progresses, the bodies become smaller and slightly more dispersed. No relation of Golgi apparatus to the secretory phenomenon is apparent.
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  • 9
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The diploid number of twenty-six chromosomes was found in the mature parthenogenetic female-producing eggs and also in the somatic cells of the female embryos developing from such eggs. In the maturation stages of a few of these eggs the chromosomes were markedly larger than in the corresponding stages of the majority of the eggs. Whether this size difference of the chromosomes is correlated with male- and female-producing individuals has not been determined. The mature parthenogenetic male-producing eggs contain the haploid number of thirteen chromosomes, and this number was found also in the somatic cells of the young male embryos. The mature sexual eggs contain thirteen chromosomes.In spermatogenesis the secondary spermatocyte divisions are usually omitted and the secondary spermatocytes develop directly into the motile spermatozoa containing thirteen chromosomes. A few, however, of the secondary spermatocytes divide, forming spermatids containing fewer than thirteen chromosomes. These cells develop into the non-motile and rudimentary spermatozoa.The motile spermatozoa containing thirteen chromosomes unite with the parthenogenetic male-producing eggs containing thirteen chromosomes, thus producing the fertilized eggs with the diploid number of twenty-six chromosomes. These fertilized eggs develop into female-producing females which reproduce parthenogenetically.
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  • 10
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 435-478 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The perivisceral fluid of Pheretima indica (Horst) contains five types of leucocytes: lymphocytes, monocytes, granulocytes, lamprocytes, and linocytes. The granulocytes differentiate either from free lymphocytes, from peritoneal epithelial cells lining the leucocytopoietic organs, or from lymphocytes (hemocytoblasts) embedded in these organs. The lymphocyte is a hemocytoblast. The eosinophilic granulocyte is the most numerous of the several types of granulocytes. Morphologically and tinctorially, it resembles the eosinophil of fishes. The eosinophil granule is thought to arise either by a ripening of a basophil granule and to pass through a metachromatic phase during this process, or by being formed immediately without such a ripening process in small hemocytoblasts. The stimulus for the excessive production of eosinophils is thought to be the degree of infection of the leucocytopoietic organs by a species of the gregarine, Monocystis.A series of segmentally arranged leucocytopoietic organs is described for the first time in the oligochaetes. These organs are essentially foldings of the septa and offer sacculations in which leucocytopoiesis may take place.A discussion of the possible phylogeny of the hemocytopoietic organs of the invertebrates and vertebrates is given.
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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: This study concerns the voice box or syrinx of the fowl in its possible relation to sex. Although neither hens nor capons crow, ovariotomized hens have been known to do so. It appears that a slight sexual dimporphism exists in the syrinx of certain fowls, and it was thought that a particular form might be essential to the act of crowing. However, no sexual dimorphism is apparent in the syrinx of the Brown Leghorn fowl.The syringeal structures of crowing birds (cocks and ovariotomized females) contain no features which cannot be demonstrated in normal females. Variations were found in the syrinx in this breed and in other breeds, but they had nothing to do with sex. There is a gradual ossification with increasing age and size. It may be concluded that there is no apparent reason why the female fowl should not crow, provided it had the instinct to do so properly developed. The sex hormones, if they act in voice production, must act entirely through the conditioning of the central nervous system.
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  • 12
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929), S. 519-529 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The liver has a rhythmic function with alternating assimilatory and secretory stages. The height of the assimilatory stage in rabbit's liver is characterized by the following qualities: All the cells are usually expanded and contain much glycogen and few bile components. The bile capillaries are narrow and generally empty. The glycogen content is high (about 13 per cent); the total glycogen weight is also high (about 17 grams). The liver has a relatively heavy weight (about 140 grams), a large volume, notably firm consistency, and a light brown color.The secretory stage at its height has the following characteristics: All cells are shrunken and are rich in bile components, but contain little glycogen. The bile capillaries are expanded and filled with secretion (fixation with barium chloride). The glycogen content is low (about 1 per cent), and the total glycogen weight is also low (about 1/2 gram). Weight of liver low (about 50 grams). Volume small and consistency fairly flaccid. Color dark reddish brown.Between these two extremes are various intermediary stages. Such variations as these probably occur during the normal functioning of the liver in man and also in other animals.
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  • 13
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 48 (1929), S. 1-43 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The parenchymal cells in the parathyroids of Rana catesbeiana (Shaw) are found to undergo a very curious cyclic change. The cytoplasm is broken down by a process of cytolysis. The nuclei are decomposed by chromatolysis and pycnosis. The entire parenchyma is finally liquefied, except for a layer of cells lining the capsule.The parathyroid body is reconstructed by young cells which are produced from rather definite growth centers. The process of regeneration begins some time before cytolysis is completed and continues until the entire organ is restored.The cytolytic and regenerative processes transpire in such sequence that the amount of apparently healthy tissue present at any one time is a rather large portion of the total mass normally present.The relationship between the parenchymal tissue and the stroma of the parathyroid is described.
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  • 14
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two types of cytoplasmic inclusions, differing in reactions to vital dyes and to osmic fixation and impregnation have been demonstrated in Peranema trichophorum. The mitochondria are rod-like and lie in more or less spiral rows, forming a single layer beneath the periplast. They are stained supravitally with Janus green, but not with neutral red. They may be demonstrated by staining in iron hematoxylin after Mann-Kopsch fixation. They are also blackened in prolonged osmic impregnation, but are bleached readily with hydrogen peroxide.The small spherical osmiophilic inclusions are scattered in distribution, although sometimes more numerous in the anterior third of the organism. These bodies are stainable supravitally with neutral red, neutral violet, and brilliant cresyl blue. They are densely blackened in osmic impregnation, and are not bleached in the usual treatment with hydrogen peroxide. They are not however, demonstrated by Mann-Kopsch fixation and iron hematoxylin. After being stained supravitally with neutral red, these inclusions may be blackened under direct observation by exposure to osmic vapor in hanging-drop preparations.
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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 purpose of this study was to determine whether structural elements of the cytoplasm can be demonstrated to be specifically concerned with certain physiological processes that are experimentally induced in tissue at the time of fixation. The methods for bringing into view variations in cell structure correlated with cell activity were as follows: the increase of the process of secretion by subcutaneous injection into the living animal of phenol red and of urea; the increase of the process of reabsorption by injection of glucose: the inhibition of reabsorption of sugar by injection of phlorhizin.Variations of the same magnitude in the form, position, quantity, and interrelationships of granules, globules, chondriosomes, and Golgi substance were found to occur in normal untreated animals and in those treated experimentally. Some evidence was found that in cells of the proximal tubule a characteristic form of Golgi body appears which seems to be correlated with increased reabsorption of sugar.
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  • 16
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The rate of locomotion in Amoeba proteus is dependent upon the nature of the substratum, the nature of the different divalent and monovalent cations present, and the ratio of the amount of the monovalent cations to the amount of calcium or strontium. Calcium is more efficient than strontium in antagonizing potassium. Magnesium and barium do not antagonize potassium. The four monovalent cations studied in antagonizing calcium are efficient in the following order: Na〉K〉Li〉Rb. Calcium and potassium are more effective against antagonistic cations when combined with chlorine than when combined with phosphate.
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  • 17
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the ovary of the rat the ova arise by proliferations from the germinal epithelium, all cells of which are potential ova. This proliferation begins with the differentiation of the gonad, and may last as long as 369 days postpartum. The embryonic ovary is filled with ova which pass through the typical maturation phases. This continues until five days after parturition. These ova degenerate, none being found in the ovary of the twenty-day rat. After the fifth day postpartum, nuclear development in the ova changes until, by the twentieth day, no typical maturation phases are present. With the degeneration of the embryonic ova the ovary takes on the adult structure.The ovary of the adult female rat shows a modified type of meiosis in the germ cells, while that of the embryo shows the typical phases, indicating that this is the primitive type, with the modified form an acquired characteristic.Ova in a single rat may show both twenty-one and thirty-one chromosomes.Follicle cells are formed from the cells of the germinal epithelium and, like the sex cells, may have both forty-two and sixty-two chromosomes in a single follicle. The lutein cells also show both forty-two and sixty-two chromosomes in a single corpus luteum. The chromosomes of the lutein cells enlarge with the expansion of the cell to a size greatly in excess of the chromosomes of the somatic cells. The theca interna is derived from the tunica albuginea.
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  • 18
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 47 (1929) 
    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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  • 19
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The significance of the ultimobranchial body has been the object of a comparative study of the structure in twenty-four species of urodeles. In nineteen of these it has not hitherto been described.Caudal to the last branchial arch, it develops as a thickening and later as an outpushing from the ventral wall of the pharynx. Due to the growth mechanics of the region, it comes to lie obliquely to the pharynx, ventral to it, and dorsal or dorsolateral to the pericardial cavity in its anterior region. It persists throughout life as an epithelioid or epithelial structure, usually of irregular shape, frequently containing vesicles; in some cases it exhibits a considerable amount of secretory activity of variable quality. Except in Amphiuma and Necturus, where it is regularly paired, and in occasional instances in individuals of other species, where it occurs on both sides, it is usually present on the left side only. Its occurrence is constant in all of the species of urodeles for which it has been examined.It is variable in size, form, and position. This, together with the quite inconstant indication of secretory activity, marks it as a structure of little or no physiological significance. ‘Colloid’ is, however, present in some instances, and hence a comparison with the thyroid was considered.
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  • 20
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    Journal of Morphology 47 (1929), S. 531-553 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The external genitalia and the internal reproductive organs are described. Compound gonads, with a normal development of testicular and ovarian tissues, are found in the positions of the gonads of normal individuals. The genital ducts arise in both types of tissue and serve as common ducts.It is demonstrated microscopically that the male tissue has one and the female tissue two sex chromosomes. The diploid number (or nearly so) is present in both tissues. This is the constitution of the normal sexes.The origin of the gynandromorphs is accounted for by assuming either the theory of dispermy in the binucleated egg or chromosomal elimination.
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  • 21
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    Journal of Morphology 47 (1929), S. 555-587 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The germ cells of Lebistes are found in cysts; the younger cysts are toward the cortex. Mitochondria and Golgi apparatus are present. During maturation leptotene, bouquet, pachytene, and diakinesis figures are seen. The spermatocyte chromosomes number twenty-three; an X-Y pair is probably present, though the evidence is not conclusive. In spermatid formation the centriole divides to form a rodlet and an axial filament; the nucleus segregates into two materials, one of which is extruded; the remainder first contracts to a cup, comes in contact with the rodlet, then again forms a sphere. The mitochondria are arranged along the proximal part of the axial filament; the sphere flattens and elongates; the rodlet sinks into the head substance and is enfolded by it. The Golgi remnant is sloughed off with the residual cytoplasm, which disappears at the same time the Sertoli cells show an increase in size, suggesting their ingestion of the spermatid remnants. The mature sperm form spermatozeugmen, which are stored in the testicular canal; they are transferred to the female by aid of the modified anal fin.
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  • 22
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    Journal of Morphology 48 (1929), S. 81-103 
    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 of the embryology of the rabbit in races of large and small adult size shows a consistently more rapid rate of cell multiplication and of increase in mass in large-race embryos than in those of small race.This more rapid rate of growth is transm tted by and influenced equally by sperm and egg cell, as is shown by the results of reciprocal crosses.Rate of differentiation is independent of rate of growth and unaffected by it. Consequently, embryos of the large race have attained greater size than those of the small race at corresponding stage of differentiation.The fundamental difference in rate of growth is already in evidence in forty-eight-hour embryos and becomes increasingly clear at later stages. Embryos produced by the large race have undergone about one more cell division at forty-eight hours after mating and so are approximately in the thirty-two-cell stage when embryos of the small race are in the sixteen-cell stage.
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  • 23
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    Journal of Morphology 48 (1929), S. 153-171 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A description of the gross embryology of the sex apparatus of a common diplopod, the corn millipede. The life-cycle of this animal involves eleven instars extending over a period of three years.In the male the true first legs are shed at the ninth ecdysis and the large clasping appendages are substituted through the last three instars. In the region of the second body somite the fused coxal plate and the penes are developed at the final molt; the second appendages are reduced at this time. The greatest changes occur in the region of the seventh somite, where the legs are shed about the eighth ecdysis and the gonopods developed through the remaining instars. It is evident that these gonopods arise as a modification of the sternites of the seventh somite.In the female the second legs are reduced to vestiges at the final molt. The structures at the mouth of the oviducts are developed from the surrounding tissues and the modified sternites of the reduced second legs. These changes are in progress as early as the seventh instar, but the greatest changes occur at the final ecdysis.
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  • 24
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    Journal of Morphology 48 (1929), S. 253-279 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Technique. This work is based not only on the fixed preparations, but also on fresh cover-slip preparations treated with neutral red or 2 per cent osmic acid for a short time.Golgi elements and fatty yolk. The Golgi elements are hollow vesicular bodies with a distinct osmiophilic rim and a central osmiophobic substance. In the youngest oocyte they form a circumnuclear ring. Gradually the vesicles spread out, grow in size, store up fat in their interior, and give rise to the fatty yolk. On account of their higher refractive index, due to the presence of fat, the Golgi vesicles can be occasionally seen even in the young oocytes without any treatment.Mitochondria. The mitochondrial granules also form a circumnuclear ring and are later distributed uniformly.Albuminous yolk. The albuminous yolk is nucleolar in origin. Early in oogenesis, the nucleous buds off small, homogeneous, and highly chromatic particles in the cytoplasm, which sooner or later disappear. Subsequently, the nucleolus becomes less chromatic and develops vacuolar bodies in its interior, which, becoming vacuolated exactly like the parent nucleolus, migrate into the the cytoplasm. These bodies become more and more chromatic and travel toward the periphery of the egg, where they grow in size. Ultimately they break down into small, homogeneous, and highly chromatic bodies which are the definitive albuminous yolk spheres and which subsequently grow enormously in size.
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  • 25
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    Journal of Morphology 48 (1929), S. 281-316 
    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 Uromastix hardwickii retains many primitive features and shows great resemblance and relationship to that of Sphenodon. The heart is typically reptilian. Two systemics and a pulmonary arch arise from the ventricle. The conus arteriosus is absent. The carotids arise together from the right systemic by means of a small common carotis primaria. A very well-developed ductus caroticus connects each carotid with the systemic arch of its side. The ductus arteriosus (ductus Botalli) is absent.The dorsal aorta is formed by the union of both the systemic arches. The left systemic joins entire while the right one, which is termed systemicocarotid trunk, gives off the carotids, the vertebral, a single subclavian, and two pairs of parietal arteries, before the union. Anterior epigastric arteries are altogether absent. The dorsal aorta gives off fifteen pairs of parietal arteries which are segmentally arranged. All the main branches supplying the alimentary canal and other viscerala organs arise independently of one another, there being no such combination as is found in Varanus.
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  • 26
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Direction of peristalsis of the dorsal vessel in prepupa, chrysalis, and adult of Lepidoptera is not constantly forward; phases of forward peristalsis alternate with phases either of backward peristalsis throughout the whole dorsal vessel or of diverging waves originating in the third to fourth abdominal segments, proceeding backward and forward. Periodic reversal in the silkworm begins twenty-four hours after spinning, forty-eight before pupation. Pupation occurs during a vigorous backward phase. Soon after pupation, and sometimes during pupation, backward phases consist of diverging waves. Later, and in the adult, complete reversal intermittently occurs. Backward phases in the pupa are long (e.g., fifteen minutes), the average rate slow and variable, quickening at eight to ten days to that of the adult. Any long backward phase shows a gradual slowing down, except approaching pupation when the pulse quickens to equal that of forward beating. Average rate of forward beating is constant at constant temperature, but absolute rate in a long phase gradually slackens. Pauses (sometimes one and one-half hours long in older pupae) often follow forward phases. Alternating phases in the adult, compared with the pupa, are short, about one minute and usually less than one hundred beats. In old moths the phases become still shorter, often being reduced to single beats. Opposing waves occasionally conflict. Periodic reversal occurs for hours after excision of the dorsal wall with the pericardium and heart. As in ascidians, back pressure cannot explain reversal.
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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: Following the isolation of sperm in the epididymides of male guinea-pigs by the separation of this organ from the testis, the animals were found to remain fertile for periods varying from twenty to thirty-five days, whether they were allowed to mate but once during this period, or five times during the period, or twenty times during the period. Motile sperm were found as long as fifty-nine days after the operation. It was concluded, on the basis of these data, that an aging process which sperm isolated in the epididymis undergo is more important than the number of matings (up to at least nine or ten) in the determination of the period during which sperm motility is retained and in the determination of the period during which fertilizing capacity is retained.If the behavior of sperm isolated in the epididymides can be taken as an indication of the processes of sperm development which occur normally, the epididymis would seem to be an organ in which sperm may at one time be attaining an optimal functional state and may at another time be aging and becoming incapable of functioning. The possible significance of this suggestion for the rǒle of the epididymis in sperm development and for the history of sperm after they leave the testis is discussed.
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  • 28
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    Journal of Morphology 48 (1929), S. 563-584 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: From the structure of statocysts, in the so-called phylogenetic tree of the Cephalopoda, the genus Scaeurgus is to be placed on the same branch as Polypus.Meleagroteuthis has the same number of processes as Watasenia, Enoploteuthis, Abralia, Illex, and Stigmatoteuthis, which have ten processes, but in this genus the structure of statocysts seems to be tolerably well developed. For this reason, the author places this genus as a branch between Abralia and Illex.Those three genera - Gonatus, Sthenoteuthis, and Onychoteuthis - which have eleven processes in a statocyst are to be placed in the same branch as Berryteuthis, Gonatopsis, Ommastrephes, Eucleoteuthis, Moroteuthis, and Symplectoteuthis, which have the same number of processes; of these, Gonatus, which has the most primitive structure of the statocyst, is to be put in the lowest position on that branch; but Sthenoteuthis, which has the same structure of the organ as Ommastrephes, is to be placed on the twig near Ommastrephes; and, lastly, Onychoteuthis has the same organ as that of Moroteuthis, which fact induces the author to set this genus in the position nearest to Moroteuthis.The statocyst of Lolliguncula corresponds exactly to that of Loligo, which has twelve processes; this condition puts this genus on the same twig as Loligo.
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  • 29
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    Journal of Morphology 48 (1929), S. 611-625 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: By the use of a new technique it was possible to demonstrate the Golgi granules about the idiosome of spermatids and in the so-called Golgi bead of the mature spermatozoon. Other osmiophile granules in the cytoplasm, assumed to be Golgi granules, aggregate during metamorphosis into groups which formed neutral fat spheres, giving stains with both sudan III and scharlach R. Evidence is adduced supporting the view that the Golgi apparatus is a lipin and probably a phospholipin. The fat spheres produced are probably a result of fatty degeneration in the residual body of the spermatid. They may also serve as the source of lipin in Popa's ‘Lipo-gel’ phenomenon.
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  • 30
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    Journal of Morphology 47 (1929), S. 1-36 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The first spermatocytes of Circotettix verruculatus have eleven chromosomes. Five of these are regularly atelomitic and three are telomitic. The other three are variable and may have both diads telomitic, both atelomitic, or one diad telomitic while the other is atelomitic. The locus of fiber attachment and, consequently, the form of the chromosome are constant for the individual. The point of fiber insertion is known to be inherited according to mendelian principles, and is, therefore, a measure of the frequencies of the telomitic and atelomitic diads in a group of individuals.Samples of five geographically different populations were studied with respect to the proportion of atelomitic to telomitic diads in the three variable tetrads. The proportion for each of the three chromosomes was compared with that for the corresponding tetrads from the other localities. The data were subjected to statistical analysis, and significant differences between some of the groups were found in the proportion of atelomitic to telomitic diads in corresponding chromosomes.A possible correlation between these cytological differences among the various localities and the formation of geographical races or subspecies are discussed. An inversion of the portion of a chromosome, which causes an apparent, although not a real, change in the locus of fiber attachment, is suggested as the origin of atelomitic chromosomes. The effect which heteromorphism of synaptic mates may have on crossing-over is considered.
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  • 31
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    Journal of Morphology 47 (1929), S. 227-259 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A histological study was made in the guinea-pig of the distribution of melanin pigment in the normal dark-eye and in various mutant types, such as the brown type of dark-eye (b), light and dark salmon-eye (sm), dark red-eye (crB), brown red-eye (crb), albino (ca), pink-eye (p), and pseudopink-eye (P sm b). The genes which affect pigmentation in the eye have definite qualitative or quantitative effects on the production of melanin. Eyes of the genetic constitution ca, p, or sm possess very little pigment. But eyes which have the dominant allelomorphs of these genes, C, P, or Sm, have a large amount of pigment. The non-yellow gene, cr, and the brown gene, b, cause the deeper retinal layer, which is normally intensely pigmented throughout its entirety, to become less pigmented. There is a corresponding reduction in the melanin in the pigmented areas of the iris and choroid. In all types of eyes with reduced pigment, such as the albino, pink-eye, and pseudopink-eye, pigment persists in the deeper retinal layer even when it is almost absent from other regions. Moreover, in all eyes which have less pigment than the normal type there is a decided tendency for chromatophores to be located adjacent to blood vessels. This tendency is outstanding in the iris and quite noticeable in the choroid.
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  • 32
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    Journal of Morphology 47 (1929), S. 335-413 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An attempt is made to define lips, and on Danforth's interpretation of homology, homologous lips are found at certain stages of development in some representatives of all classes of vertebrates. The primary lips characteristic of selachians, after the maxillary and premaxillary bones have developed within the territory of the upper lip (toadfish, cod), may disappear (trout, Spelerpes), accompanied by a forward migration of the lower jaw. The secondary lips of higher forms are first indicated in certain teleosts and amphibians. Lips vary in structure to accord with their physiological functions, whether sensory, prehensile, or adhesive. Lips of the cod are highly sensory; those of the tadpole and of grazing animals, in different ways, are notably prehensile; the lips of petromyzon and the vampire, having abundant villi, are most effectively adhesive. Therefore, the smaller villi of the lips of suckling animals are presumably for tight adhesion to the nipple. The opossum and rat, however, nurse before their lips have developed. No free macroscopic villi are found on human lips, but there is a zone of thick epithelium tending to form villi. Such a zone is shown to be a widespread feature of vertebrate lips.
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  • 33
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: During the past few years many functions have been assigned to the epididymis which have been supplementary to its rǒle in sperm storage and to its secretory activity. One of these, the suggestion that sperm attain full maturity and are strengthened in consequence of some action of its secretion, has been reinvestigated as the first part of a study which is intended to include other aspects of the problem.No evidence in support of the theory was obtained from a series of experiments on various mammals representing a repetition and extension of earlier work. On the contrary, the strengthening and attainment of full spermatozoon maturity would seem to be the outcome of changes which are inherent in the sperm themselves. It is suggested, therefore, until other aspects of the subject can be reinvestigated, that the epididymis is simply a reservoir for sperm in which the processes of sperm development which start while they are still contained in the testis are free to continue because of the favorable environment present in the epididymis.
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  • 34
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    Journal of Morphology 48 (1929) 
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  • 35
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    Notes: It was found that thyroid deficiency in the albino rat (Mus norvegicus albinus) is followed by a trend to increased concentration of epinephrin in the suprarenals. The basis of this lies in the relatively greater retrogression of the cortex as contrasted with the medulla which becomes a relatively greater proportion of the organ as a whole. Confirmatory evidence is found in cell counts per unit area and the part of the disappearance of lipoid from the cortical cells of the suprarenals of thyroidless animals.
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  • 36
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    Journal of Morphology 48 (1929), S. 123-151 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: From a study of over 1000 mothers, the female chromosome number appears to be 2N = 22; N = 11. The male number has not been exactly determined, but is presumably not haploid. Only one maturation division occurs in the parthenogenetic egg, and the authors have seen only one in the sexual egg. During the growth stages of the eggs, the chromatin is totally obscured by a large amount of deeply staining nucleolar material which exhibits several phases. Ultimately, this material is apparently absorbed into the ooplasm. Just before the egg is laid, the ovoid chromosomes, in late prophase or in metaphase, are seen in a germinal vesicle situated always at one side of the egg. The maturation division occurs immediately after egg laying. A degenerate body, hitherto undescribed, is noted in the ripe parthenogenetic egg, situated at the pole opposite the germinal vesicle. It is believed to arise by reorganization of nucleolar substance. The body in the sexual egg desribed by Weismann and Ishikawa ('91) as the Paracopulationzelle is noted and its interpretation by these authors questioned, but, for lack of sufficient evidence, no counter-explanation is offered. The possible relation between experimental sex control and the time of maturation division in the parathenogenetic egg is discussed.
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  • 37
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    Journal of Morphology 48 (1929) 
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  • 38
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    Notes: A histological study has been made of a series of Phrynosoma testes taken at frequent intervals throughout the year. As it was important to differentiate between the amount of interstitial tissue and the number of cells, it was necessary to take into account the percentage of tissue, total testis volume and the number of cells per unit volume.The results show a definite interstitial-cell cycle. Volume of interstitial tissue and size of individual cells are greatest during the breeding season, but the interstitial-cell number is then minimal. The maximal number of interstitial cells occurs after the close of the breeding season. There is, apparently, no reversion of interstitial cells to a connective-tissue-cell type.The above changes are correlated with the spermatogenetic cycle and with increases in total tubule length, in tubule diameter, and in testis volume. The time in which important changes in ovarian volume occur and at which ovulation takes place is coincident with the testicular changes.Interstitial cells have been stated to have no endocrine function for the reason that their number is at a minimum during the breeding season. If, however, interstitial tissue is responsible for sex characters and activity, the present work would indicate that it is the volume of tissue, and not the number of cells, that is important.
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  • 39
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    Journal of Morphology 47 (1929) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 40
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    Journal of Morphology 47 (1929), S. 37-87 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The vesicular nucleus of this amoeboflagellate is similar in structure in both phases of its life-cycle. It has a fairly large caryosome surrounded by a pericaryosomal area in which there are small oxyphilic pericaryosomal granules on a fine reticulum. On the inner surface of the definite caryotheca is a layer of epithecal chromatic granules.Nuclear division is similar in both amoeba and flagellate phases. During the prophase the nucleus enlarges, and the expanded caryosome becomes resolved into basophilic and oxyphilic components and assumes either an oblong, dumb-bell, or spindle shape. The pericaryosomal granules enlarge, shift about, and eventually become arranged in an equatorial band around the elongated caryosome. In the metaphase the equatorial plate of chromosomes appears after the inward migration of the pericaryosomal granules, accompanied by the formation of a definite intranuclear spindle, usually with polar masses, polar granules, and a centrodesmose. After the poleward migration of the daughter plates of chromosomes in the anaphase, the telophase constriction of the nuclear membrane produces two daughter nuclei with a portion of the spindle remaining outside. The epithecal layer of granules remains in place on the nuclear membrane during the entire process of mitosis. Plasmotomy normally follows mitosis, but may be delayed, giving rise to multinucleate individuals. In the flagellate the blepharoplast usually divides simultaneously with, but independently of, the nucleus. There are many divergences in the details of mitosis, but these are thought to be variations of one type of division rather than examples of different processes.
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  • 41
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    Journal of Morphology 48 (1929), S. 543-561 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The parietal fossa or pit is situated in the middorsal line between the ear capsules. From its floor four (sometimes only two) apertures lead into the ear capsules. The anterior apertures are the foramina of the endolymphatic ducts; the posterior ones are the fenestrae. Through the fossa each endolymphatic duct passes from its formen to its external aperture in the dorsal integument, describing in its course a loop with the convexity directed anteriorly. The part of the duct involving the loop is enlarged into an endolymphatic pouch. Into the angle of this loop a small muscle is inserted which is a continuation of the anterior trunk muscles, or one taking a more lateral origin from the edge of the fossa. The fenestra may or may not be closed by a definite fenestral membrane. The posterior semicircular canal (posterior utriculus) bears a peculiar relation to the fenestra. The endolymphatic pouch, like the sacculus, contains otoconia, and sometimes siliceous sand grains. Various functions have been assigned to the endolymphatic organ. There is no convincing experimental evidence as to its significance.
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  • 42
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    In:  Scientia, Milano, Gustav Fischer, vol. 23, no. 3, pp. 375-384, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1929
    Keywords: Seismology ; Geothermics ; Seismicity ; Tectonics
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  • 43
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    In:  Physikalische Zeitschrift, Milano, Gustav Fischer, vol. 30, no. 3, pp. 230-231, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1929
    Keywords: Seismology ; Elasticity ; Waves ; Inelastic ; Fluids
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  • 44
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    In:  Gerlands Beiträge zur Geophysik, Milano, Gustav Fischer, vol. 22, no. 3, pp. 100-102, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1929
    Keywords: Seismology ; Seismometer ; Nearfield
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  • 45
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    Bornträger
    In:  Professional Paper, Handbuch der Geophysik, Volume 4: Erdbeben (finished), 12 + 1202 S., Berlin, Bornträger, vol. 3, no. VIIa, pp. 1-150, (ISBN: 3-540-23712-7)
    Publication Date: 1929
    Keywords: Review article ; Seismology ; Waves ; Wave propagation
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  • 46
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    In:  Professional Paper, Handbuch der Geophysik, Volume 4: Erdbeben (finished), 12 + 1202 S., Berlin, Bornträger, vol. 3, no. VIIa, pp. 151-263, (ISBN: 3-540-23712-7)
    Publication Date: 1929
    Keywords: Review article ; Seismology ; Instruments ; Seismometer
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  • 47
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    Bornträger
    In:  Professional Paper, Handbuch der Geophysik, Volume 4: Erdbeben (finished), 12+ 1202 S., Berlin, Bornträger, vol. 3, no. VIIa, pp. 264-298, (ISBN: 3-540-23712-7)
    Publication Date: 1929
    Keywords: Seismology ; NOISE
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  • 48
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    Journal of Morphology 45 (1928), S. 1-45 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Five characters-flatness, elongation, posterior pointedness, delay in division of the body, delay in completion of mitosis-are so distributed among the subdivisions of the Opalinidae as to involve either repeated fortuitous appearances of these characters, a thing not to be believed, or trends resident in the germ plasm. The Ophryoscolecidae show similar distribution of two sets of characters. In the Salpidae there is evidence of trends toward: coiling of the gut; decrease in number, size, regularity, and symmetry of body muscles; simplification and degeneration of the eyes. These qualities appear first in the phylogeny in the chain Salpas, the final phase in the life-cycle. In the course of the evolution the solitary Salpas become more and more modified in the same directions, until, in the most highly modified species, the muscles and eyes are as much modified in the solitary Salpas as in the aggregated. These changes, not disadvantageous but rather adaptive in their beginning in the colonial individuals, are harmful to the solitary Salpas, yet the degeneration is, by precocious development, thrown back onto the earlier phase of the life-cycle, the solitary stage. Precocious development is not purely utilitarian, but may be more fundamental, biological.Evolution is discussed in terms of trends resident in the germ plasm, their origin in connection with mutations, their growth, decrease, disappearance, branching; auto-evolution. Discussion is from the standpoint of the germinal stream, internal factors of evolution being emphasized.
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  • 49
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    Journal of Morphology 45 (1928), S. 187-207 
    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 description of an organism, externally resembling Müller's larva among the polyclads, collected in the plankton of Monterey Bay, California, during the spring and summer months. Internally, the organization of the various systems is unique. In some respects it bears a certain resemblance to a polyclad in early stages of development; in other regards it approaches the rhabdoceles, more particularly the Acoela. Its more exact relationships are obscured by the fact that, although the larger specimens are not more than 0.7 mm. in length, the sex organs, both male and female, are fully developed and functional. Furthermore, the plan of these systems is unlike that of any turbellarian hitherto described. Whether this organism represents a case of paedogenesis or is a fully developed adult is unknown at present, but in any event the various systems are described and an attempt is made to give it a fairly definite systematic position.
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  • 50
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    Journal of Morphology 45 (1928), S. 121-185 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An histological and cytological study of the postembryonic history of the fat-body in Pteronidea ribesi (Scopoli) and Diphadnus appendiculata (Hartig) (both Tenthredinidae) and in Macrocentrus ancylivora Rohwer (Ichneumonidae).The two principal components of the fat-body are the urate-storing excretory cells and the fat-cells.The development and behavior of the excretory cells, especially during the metamorphosis, are described, and in Pteronidea their origin is traced to leucocytes which have become associated with the fat-cells.In the albuminoid inclusions found in the fat-cells two types of substance are distinguished: (a) a basophile material, of nuclear origin, which appears only during the metamorphosis; (b) an acidophile material which appears already during the early larval stages in Macrocentrus, but in Pteronidea is formed only during the metamorphosis and in association with the basophile material. It is thus found that albuminoids formed slowly during larval life may exist from the beginning in the form of acidophile spheres, as occurs in Macrocentrus. But those formed rapidly during the metamorphosis, in all the forms studied, are formed in association with a basophile material derived from the nucleus.The significance of intracellular changes during the metamorphosis is discussed, and the final disposition of the cell inclusions as well as of the fat-cells themselves is described.
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Amoeba proteus was raised in a modified and diluted Ringer solution. When the pH of this culture medium became less than 6.0, the normal activities of the amoebae were interfered with; and when a still lower pH was attained, the amoebae died off. The same was true when the pH became greater than 8.0. At neutrality the activities were subnormal, very dark, and rounded. The rate of locomotion of amoebae raised in solutions with a pH less than 7.0 showed a maximum rate of locomotion at pH 6.6, which decreased as the pH changed in either direction, dropping to a very low rate at pH 7.0 and above and also below 6.0. For amoebae raised at a pH above 7.0 the rate was maximum at pH 7.6 and decreased as the pH changed in either direction; it was low at pH 7.0 and below and also above 8.0.On increasing the external osmotic pressure of the medium it was found that the effects caused varied somewhat with the hydrogen-ion concentration. Small increases in osmotic pressure decreased the rate from the normal at pH 6.0 and 8.0, increased it at pH 6.6 and 7.6, and did not affect it at pH 7.0. Osmotic pressures above that produced by M/20 lactose caused locomotion to cease in a short time at all pH values.
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    Journal of Morphology 45 (1928), S. 209-231 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The highly specialized cranial musculature of the toadfish is characterized by the following features: 1Absence of intermandibularis and branchiomandibularis muscles.2Presence of levator premaxillaris muscle.3Very large branchial chamber, the outer wall of which is formed by seven branchiostegal rays connected by a strong fascia provided with muscles (oblique levators and adductors).4Highly developed masticator muscles (adductor mandibularis and pterygoids).5The rectus abdominis, sternohyoid, and hyohyoid muscles are attached by a median aponeurosis to the hyoid and basibranchial elements and directly to the hypobranchial cartilages; this muscle complex depresses the buccal floor in opposition to the geniohyoid.6The pelvic fins are in the jugular position.7Two narrow muscles connect the cleithrum with the fourth ceratobranchial.8The cranial musculature is obviously adapted to a carnivorous habit and particularly for increasing respiratory capacity under asphyxial conditions.
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  • 53
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    Journal of Morphology 45 (1928), S. 293-398 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Blindfolded persons walk, run, swim, row, and drive automobiles in clock-spring spiral paths of greater or less regularity when attempting a straightaway. The spirals turn either right or left in one and the same individual, and may do so even in one experiment. But either right or left turns predominate in the great majority of individuals, often to a high degree. The paths show marked individuality, and there is some ground for thinking there exists a correlation between temperamental differences and general character of path.The mechanism which produces the spiral path is not located in the locomotor organs, but in the central nervous system and is probably identical essentially with the spiral mechanism in other motile organisms, all of which move in spiral paths when there are no guiding senses to direct the path. The clock-spring spiral in man is interpreted as the expression in two dimensions of space of a helical spiral mechanism which seems to exist in all motile organisms moving in three dimensions of space and in amebas which move in two dimensions. In a large number of lower organisms the number of body lengths per spiral turn is almost constant, being about 4.5. The smallest regular swimming spirals in man are very close to this value, but the smallest regular walking spirals are somewhat larger. The fundamental spiral mechanism seems to be of molecular dimensions, and there seems to exist a demonstrable locomotor bilateral asymmetry in very nearly, if not quite, all organisms.
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  • 54
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    Journal of Morphology 45 (1928), S. 259-292 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The digital disks of the tree frogs are covered ventrally with a superficial layer of vertically elongated, fibrous, and distally free cells between which there empty a series of convoluted mucous glands. The latter are surrounded and, in the larger-disked species, divided into blocks by sheets of collagenous fibers. The glands are emptied by the squeezing together of the collagenous fibers when the body weight exerts a pull on the terminal phalanges. The disks function by friction, cohesion, and adhesion.The digital-disk apparatus was fully established before certain groups of frogs became arboreal. It is retained in others which have reverted to the terrestrial habit. The intercalary cartilage increases the efficiency of the apparatus. It did not arise in phylogeny until after the apparatus was developed.As the digital disks vary in extent in both arboreal and terrestrial species, arborealism seems to have resulted from a chance occurrence of large disks in the smaller-bodied forms; at least, there is no progressive modification of the digits toward particular habitat requirements.The subarticular tubercles of many Salientia develop typical climbing apparatus. This may or may not be correlated with an arboreal habit. In the species with the largest subarticular tubercles no apparatus is present. Arboreal salamanders exhibit no special climbing mechanism, but adhere by pressing their moist integument against the substratum.
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  • 55
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    Journal of Morphology 45 (1928), S. 399-439 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this study the problem of the tonsil is considered in anurans. The common toad (family Bufonidae) is used as the type, and representative species of the other families are compared.In each species representative stages beginning before transformation were selected, and the lingual region of each was sectioned. Some thyroid-fed toad tadpoles which had prematurely transformed were examined. The investigations led to the following conclusions: 1Accumulations of lymphocytes occur in all the families except Hylidae.2A pair of tonsils located on either side of the tongue appear before transformation in Bufo, and persist, increasing in size through old age.3This pair has its developmental origin at or near the cephalic end of pouch II. In no other species examined do the tonsils appear as early; in almost all forms the accumulations are inconstant in occurrence, as are also some in Bufo.4The cells of the ‘tonsils’ are lymphocytes of varying sizes. They arise from the mesenchyme; later their accumulations become sites of lymphopoiesis.5This type of lympho-epithelial mass is simple in structure and has a greatly thickened epithelium, due to extensive infiltration by lymphocytes. In the connective tissue the vascular supply is abundant.6The differentiation of lymphocytes may be due to a factor of strain, arising through adjustments made during metamorphosis.7Thyroid-fed toad tadpoles transform, apparently without developing tonsils.
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  • 56
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Modifications of the gastro-intestinal tract of Nereis virens are two dorsolateral esophageal cecums, directed anteriorly and posteriorly from the point of attachment. The cecal and esophageal lumina are continuous. Each cecum is composed of acini, possessing a row of elongated cells, basement membrane, and intima. Fibro-elastic tissue is present. The elongated cells contain glycogen and fat.The hepatopancreas of Asterias vulgaris consists of two lobes in each ray, and the numerous acini empty into the bifurcated hepatopancreatic duct which leads into the pyloric stomach. The hepatic cells are columnar and contain glycogen and fat. Pancreatic cells lie in the midregion of the acini.The lobulate liver of Loligo pealii lies on the ventral surface of the duodenum. A capsular membrane envelops the organ. The acini possess basement membrane, columnar cells, and intima; their lumina anastomose, forming a common duct, which leads into the blind sac. The hepatic cells contain fat.The hepatopancreas of Melanoplus femur-rubrum consists of six cecums histologically continuous with the digestive epithelium of the pyloric stomach. Each cecum consists of simple and compound acini which empty into a duct leading to the pyloric stomach. Each acinus possesses basement membrane, columnar hepatic cells, pancreatic cells, and intima. The pancreatic cells occur in islets, usually adjacent to the basement membrane. The hepatic cells contain glycogen and fat.
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  • 57
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spermatogenesis of five guinea-pigs was studied. The spermatogonial chromosome number is approximately sixty-two plus or minus two. The primary spermatocyte number is approximately thirty-one. The spermatogonial number in the early prophase is lower than it is in later stages. This condition is due to late fragmentation of the large chromosomes found in the earlier stage. A possible sex chromosome of the X-Y type may be identified. Its components segregate during the first maturation division.
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  • 58
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Virulent hay-infusion cultures of Bacillus pyocyaneus are toxic to pure-line races of three species of paramecia, but these races may acquire a tolerance for this toxic agent. Races with acquired tolerance have been grown for long periods of time in toxic, pure cultures of B. pyocyaneus by means of the daily-isolation culture method, and here the average division rate is as high as, or higher than, in the chance-mixed bacterial cultures in which these protozoa are usually maintained in the laboratory. The tolerance is lost, however, when the paramecia are removed from the toxic cultures and grown for a number of generations in cultures of non-toxic bacteria.The toxic agent that is lethal to paramecía is probably the soluble toxin of B. pyocyaneus. The investigation shows that the agent is soluble and either thermolabile or volatile. It also shows that all deleterious substances, other than the soluble toxin, known to be produced in cultures of this bacillus, are non-lethal to paramecia.Hay-infusion cultures of Bacillus enteritidis were lethal to paramecia. All attempts to develop tolerance in paramecia for the toxic agent in these cultures failed.Under the experimental conditions that prevailed, diphtheria toxin was found to have no appreciable effect upon the division rate or death rate in three species of paramecia.
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  • 59
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    Journal of Morphology 46 (1928), S. 217-239 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Notwithstanding the fact that several species of Bruchidae have been used by geneticists for several years, no cytological studies have as yet been made on any member of this family of the Coleoptera. The present paper gives a general account of the spermatogenesis of Bruchus quadrimaculatus Fabr.The spermatogonia undergo two mitotic divisions. After the second division, the nuclei remain small and very dense for some time before the beginning of the growth phase. During this interval the nuclei do not assume again the characteristics of the interkinesis stages. In the primary spermatocytes typical tetrads are formed. The chromosomes are asymmetrically V-shaped. The end of one arm of the ‘V’ fuses with the end of the corresponding arm of its synaptic mate. Disjunction takes place in the primary spermatocyte division. After the division of the secondary spermatocytes, the chromosomes become vesicular and form a reticular nucleus in the spermatid, after which the chromatin becomes deposited as a chromatin rim around the nuclear periphery. The diploid number of chromosomes is nineteen in spermatogonia and in male somatic cells, and twenty in female somatic cells. An unpaired X chromosome is present in the spermatogonia, which fails to divide in the primary spermatocyte division, but passes as a whole to one pole in advance of the autosomes. The X chromosome divides normally in the secondary spermatocyte division with the autosomes.In the method of sex determination, Bruchus does not follow the method of the majority of beetles, since most of those studied adhere to the X-Y type.
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    Journal of Morphology 45 (1928) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 61
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    Journal of Morphology 45 (1928) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 62
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A detailed study has been made of the anatomy of one of the fingernail shells, and preliminary observations on the life-history have been carried out. In its general organization Sphaerium notatum is very similar to the larger fresh-water lamellibranchs. A gastric shield, crystalline style, and style sac, very similar to those found in the stomach and intestine of Lampsilis, are present. A pair of slender muscles extending from the dorsal side of the body into the gills, and evidently not previously described, have been found. The nervous system consists of the typical three pairs of lamellibranchiate ganglia, with their connectives, accessory ganglia, and nerve fibers. Particular study was given to the statocysts and osphradia, and attention is called to the fact that the function commonly ascribed to the osphradia is incompatible with their position in the roof of the cloacal chamber.S. notatum, like all the Sphaeriidae, is hermaphroditic and viviparous. The gonads are paired racemose glands lying behind and below the stomach. The sperm-producing follicles form the anterior portion of each gonad and are somewhat smaller and more numerous than the ova-producing follicles which form the posterior portion. The young pass through the early stages of development in brood pouches in the gills and are expelled as relatively enormous individuals.Preliminary observations on the life-history indicate that reproduction reaches its height in the summer and that fertilization probably takes place during the late summer and fall.
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  • 63
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    Journal of Morphology 45 (1928), S. 599-613 
    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 spermatogenesis was made on four groups of a pedigreed strain of the moth Philosamia cynthia, and the results were compared with spermatogenesis in the wild material.Deviations from the normal number of chromosomes were observed in two groups. In some individuals the haploid number was 12 instead of 13. Giant spermatocytes were also observed with twenty-four chromosomes. In other individuals, two haploid numbers, 13 and 14, occurred in the same testis.The twelve-chromosome condition is due to linkage of two chromosomes during the late prophase of the primary spermatocyte. The double chromosomes thus formed appeared to divide equally in both divisions. The origin of the fourteenth chromosome was not determined.Correlation of the genetic and cytological data indicates the restriction of aberrant chromosome complexes to two of the four groups and the regularity of the twelve-chromosome complex in certain families, suggesting the conclusion that a new strain arose in the pedigreed material with regard to chromosome variability and that the twelve-chromosome condition is a well-defined characteristic, partly established in some families and probably fully established in others.
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  • 64
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When Menidia eggs are fertilized with Prionotus sperm, the Prionotus chromosomes react in the Menidia cytoplasmic medium just as they do in the cytoplasm of Fundulus eggs. There is lagging, non-disjunction, and elimination of chromosomes during the early cell divisions. The mitotic behavior of the Prionotus sperm in the Menidia egg also resembles the behavior of the sperm of Ctenolabrus in the same medium. This behavior which was expected from what was known concerning the mitotic behavior of the reciprocal crosses between Menidia and Fundulus and between Ctenolabrus and Prionotus and other intercrosses between the members of these two groups is regarded as a function of the physical state of the egg cytoplasm during the division phase of mitosis. This physical character forms the earliest differential factor in the development of these hybrids and shows no correlation with the width of the cross.A comparison of nine teleost crosses, in which both the development and the early mitotic behavior are known, with a rough numerical estimate of the width of the cross brought out the fact that development is most successful in crosses between nearly related species if mitosis is normal and in distantly related crosses if mitosis is abnormal. This indicates that nuclear relationship is also a factor in the development of hybrids.
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  • 65
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    Journal of Morphology 46 (1928) 
    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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  • 66
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A chronological investigation of the histological condition of the right ovary of the domestic hen from embryos of nine days' incubation to adults of eighteen months was made. A rudiment of the right ovary is found at all times. Its composition is variable. Sixty-one per cent of the rudimentary ovaries contained medullary tissue only. Thirty-nine per cent had rudiments of cortex, in addition. The occurrence of cortical rudiments in embryonic stages is the probable basis of ovarian follicles found in the rudimentary right ovaries of adults. Primordial germ cells persist in the medullary tissue until three weeks after hatching. They subsequently appear to atrophy. The medullary cords persist through the entire period either as distended tubules or as solid cords of modified epithelial cells. Remnants of the right mesonephros persist as tubules and connect with the gonad by rete tubules. The mesonephric duct maintains a patent lumen.
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  • 67
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fetuses from forty-three gravid uteruses from sows of known breeding dates, as well as from 448 uteruses with unknown breeding dates, were studied. Growth curves are given for weight and length of fetus and for weight of fetal membranes. The weight of the fetus first reaches that of the fetal membranes between the sixtieth and seventieth days of pregnancy. Degenerate fetuses were found in 3.68 per cent of the cases. They were found at all stages of gestation. Size of litter was found to decrease from 11.4 at the twentieth day to 6.8 at the 110th day. Also, the calculated per cent of ova lost up to each ten-day stage tends to increase as gestation advances. Crowding was found to be an important factor, but probably not the only factor, in causing degeneration. Genetic factors were probably responsible for part of the resorbing fetuses.In the study of the normal fetuses, significant correlations were found between fetus length and weight of fetal membranes, as well as between fetus weight and weight of fetal membranes. Lower correlations, but probably significant, were found between total distance (spacing) between fetuses in the uterus and weight of fetal membranes. Correlations between size of fetus and total distance between fetuses were very low. As in the case of the degenerates, crowding has an important relationship to size of fetus, but is probably not the only factor involved.
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    Journal of Morphology 46 (1928), S. 563-583 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The urinogenital organs of Myrmecobius fasciatus conform to the marsupial type in both their anatomical characters and histological details. The external genitalia indicate a close relationship with the Dasyuridae.
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This peritrichous ciliate lives as an ectocommensal on the skin and gills of anuran tadpoles. Its relation to described species of Trichodina is doubtful. This study was made almost exclusively on fixed and stained material. Binary fission is similar to that in other ciliates. The horseshoe-shaped macronucleus condenses, then divides amitotically. The single small micronucleus forms a spindle containing between four and six chromosomes.Endomixis is of high incidence in the free-living Trichodinae. Encystment was not observed. At the onset of endomixis, the macronucleus disintegrates into fragments which persist throughout the process. The micronucleus undergoes three rapidly succeeding mitotic divisions to form eight nuclei. There is no evidence of chromosome reduction during these divisions. Seven of the nuclei differentiate into macronuclear anlagen; the eighth becomes the functional micronucleus. Successive cell divisions - before each of which the micronucleus divides - distribute macronuclei to daughter cells. Variations from the regular process of endomixis may arise, 1) by precocious division of endomictic parents; 2) by extra divisions of the micronucleus; 3) by less than the usual number (three) of divisions of the micronucleus; 4) by hypertrophy and early differentiation of the micronucleus into macronuclei; 5) by unusual segregation of nuclei to daughters, and, 6) from miscellaneous causes.The significance of these variations is discussed in connection with the possible origin of bimicronucleate and amicronucleate races.
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