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  • Life and Medical Sciences  (909)
  • Chemical Engineering  (524)
  • 1980-1984  (1,395)
  • 1930-1934  (38)
  • 1910-1914
  • 1982  (1,395)
  • 1930  (38)
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  • 1980-1984  (1,395)
  • 1930-1934  (38)
  • 1910-1914
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 385-413 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure of the living blood cells is described and the cells are classified in the following species of ascidians: Phallusia nigra, Ecteinascidia turbinata, Clavelina oblongata, Symplegma viride. Evidence for the genetio relationship of the various types of cells is discussed.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 455-507 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The history of the cytoplasmic components in the spermatogenesis of Gerris is, in general, like that which has been described in the Pentatomidae. The observations of fixed material have been checked by extensive studies of freshly teased preparations. During the spermatocyte growth period the chondriosomes undergo considerable increase in mass. During the maturation divisions the chondriosomes are remarkably constant in orientation with respect to the centrioles. The nebenkern arises by fusion of chondriosomes differentiated into chromophilic and chromophobic portions. The Golgi bodies of the earlier spermatocytes are vesicular bodies, the peripheries of which are osmiophilic. These are not visible in fresh preparations, but the masses resulting from their fusion in the late prophase of the first division are visible in the unfixed cells. The non-osmiophilic material inside these masses stains with neutral red in fresh preparations. Only the osmiophilic part of the Golgi masses is involved in the fragmentation to form dictyosomes. There is very suggestive evidence that the process of acrosome synthesis largely takes place inside the sac-like acroblast (Golgi apparatus). In the spermatid, material which stains, in fresh preparations, like the acroblast is never seen, except inside or attached to the acroblast, where it appears in the form of small spheres of ‘pro-acrosomic’ material, which fuse to form the acrosome.
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  • 3
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 579-619 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Haemichromis bimaculata is a tropical teleost fish which will produce eggs practically throughout the year at intervals of from three to four weeks. These eggs are of suitable size and character for embryological study, the features of special interest so far discovered being as follows: (1) The egg is oval; (2) it is attached to a substratum by its side, the blastopore being at one end; (3) the embryo always tends to develop along the side opposite that originally next to the substratum.Results obtained by reorienting the eggs previous to cleavage, and by centrifuging them, seem to show that the relation of the embryonic axis to the egg is determined either previous to laying or very soon afterward, possibly by the relation to the substratum, and is not subsequently affected by gravity or other known factors. There may be some tendency for the first cleavage plane and the sagittal plane of the embryo to coincide, but such coincidence is not at all constant or exact.
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  • 4
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 50 (1930), S. 127-142 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Color changes in Palaemonetes had been found to be inhibited in the whole abdomen by occluding the dorsal abdominal artery. Inasmuch as these chromatic responses are brought about by means of circulating hormones, it should be possible, in view of early anatomical findings, for specific substances to reach the abdomen by way of the ventral abdominal artery which has been described for so many decapod crustaceans. This paper reports a degenerate ventral abdominal artery and a ventral continuation of the dorsal abdominal artery, the latter thus being distributed to practically the entire abdomen and therefore chiefly responsible for abdominal color-change phenomena.A method is given for injecting the arteries of small crustaceans, and the entire arterial system of Palaemonetes is described and figured. Several hitherto unreported vascular structures are noted: a plexus of blood vessels surrounding the supra-oesophageal ganglion, certain branches of the ophthalmic artery leading to the eyes, and various branches of the dorsal abdominal artery in the region of the telson and uropods. The forward flow of blood in the ventral portion of the abdomen in decapod crustaceans is held to be unique.
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  • 5
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 50 (1930) 
    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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  • 6
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histological changes which occur in the digestive system and its appendages and in the muscular system of the honeybee during metamorphosis are described. Some attention is given to changes which take place in the fat-body, the silk-glands, and the reproductive system. Material of known ages was used. Observations began with the sealing of the larva in its cell and were concluded with the young bee ready to emerge from its cell. Soon after the larva is sealed in its cell, the body tissues begin to undergo a change. Larval epithelial cells lining the midgut are cast into the lumen and they are replaced by cells which proliferate from the imaginal or ‘replacement’ cells. In the fore- and hindgut the lining of the larval cells is replaced by imaginal cells whose points of origin are probably at the anterior and posterior ends, respectively, of the midgut. While the imaginal lining is being formed, the opening from the midgut into the hindgut is closed by a small portion of tissue. A part of the larval muscles are histolyzed and then re-formed from imaginal myoblasts, other larval muscles disappear entirely. The strictly imaginal muscles (e.g., leg muscles) are formed by myoblasts which congregate at the point of muscle formation. There is no evidence of phagocytosis in the honeybee during metamorphosis.
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  • 7
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 50 (1930), S. 341-359 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth of chick embryos of heavy and light breeds and the reciprocal crosses between them is described. The embryos of the heavier breed and the hybrids were found to be somewhat heavier than the embryos of the lighter breed from the tenth day of incubation to hatching time. In eggs of the same weight from the two breeds the size difference tends to disappear toward hatching time, probably due to the equivalence of the strictly limited food supply. It is pointed out that the size difference is more probably due to difference in the proportion of cells dividing at a given time than to a difference in duration of mitoses.The mortality of the hybrid embryos was intermediate between that characteristic of the parent breeds, while the percentage of monsters in the hybrids was less than that for either parent breed. There is thus some indication of heterosis.
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  • 8
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 50 (1930), S. 475-495 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Four species of iceryine coccids have been studied cytologically in connection with certain breeding experiments. These are Icerya littoralis, Icerya montserratensis, Echinicerya anomola, and Crypticerya rosae. For the three first-named species the complete chromosomal history has been established, and the evidence on the fourth, Crypticerya rosae, is sufficient to indicate that it differs in no essential respect from the others. The following résumé may, therefore, be considered to apply to all four species. The females are diploid, with a chromosome number of four, and the males are haploid, with a chromosome number of two. Oogenesis proceeds quite normally; two tetrads are formed and two maturation divisions occur in which the chromosomes are reduced to two in each female pronucleus. All eggs undergo this reduction: if the eggs are then fertilized, the diploid number is thus restored and development into females ensues; if the eggs remain unfertilized, whether in the body of a virgin or of a fertilized female, they develop parthenogenetically, with no restoration of diploidy, into haploid males. The spermatogenesis of the haploid males involves a single meiotic division, demonstrably equational in character; the accompanying cytoplasmic division is suppressed, and from each of the binucleate spermatids thus produced two spermatozoa are formed. These conditions are contrasted with the functional hermaphroditism and haploid parthenogenesis of Icerya purchasi.
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  • 9
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 50 (1930), S. 569-611 
    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 close series of ontogenetic stages from cleavage until after metamorphosis.The so-called primordial germ cells, first differentiated in the lateral mesoderm, are traced to a definitive position in the genital anlagen. Careful counts of these demonstrated that they exist in larger numbers in the younger stages and that few of them ever reach the genital anlagen where they may form a small portion of the propagative cells.Evidence is presented that the majority of the germ cells are of somatic origin. From the earliest appearance of the indifferent gonad certain cells in the germinal epithelium have been observed which were increasing markedly in size and undergoing the various changes necessary in the transformation of small cuboidal or spindle-shaped peritoneal cells with oval nuclei into large germ cells with immense polymorphic or lobate nuclei. These cells are abundant in all older individuals. All the successive stages in the evolution of a somatic cell into a reproductive cell, involving as it does an increase in size, changes in shape, and a new distribution of chromatin material, are demonstrated.
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  • 10
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The various stages in the life history of Cryptocotyle lingua are identified and described. Adults naturally occur in the intestine of fish-eating birds and mammals. They were experimentally obtained in the cat, white rat, and guinea-pig. The development of the miracidium was followed within the egg. Larval stages occur in the marine snail, Littorina littorea. The structure of the redia and cercaria is described in detail, and evidence is submitted to show that the cercaria is identical with Cercaria lophocerca Lebour, described from the same snail on the British coast. Penetration and encystment of the cercaria in the skin of the cunner were experimentally secured. Excystment of the metacercaria was obtained both in experimental animals and in vitro. The metacercariae were maintained in culture media for as long a time as is required for them to attain sexual maturity in the final host. The host relations and specificity of the parasite are discussed on the basis of infection experiments. The cercaria is compared with similar larvae and its taxonomic position determined.
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  • 11
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 50 (1930), S. 497-515 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Our observations confirm the recent findings of Krjukowa ('29) on the specific character of the Golgi material in the salivary glands of the Chironomus larva and are therefore in disagreement with the findings of Parat and Painlévé ('24).The Golgi material in the salivary glands of the Chironomus larva is present as discrete bodies having the form of crescents, rings, and rods. These are evenly deposited throughout the gland and show no makred variation in number at different stages of the physiological activity of the gland.The mitochondria are present in the form of filaments frequently concentrated in the area surrounding the nucleus and at the periphery of the cell.Neutral-red staining was never observed to color the Golgi bodies. It is suggested that the neutral-red bodies may represent the secretory material. However, it is clear that, whatever the significance of the neutral-red bodies, they are not Golgi material. Accordingly, this evidence supports the view that the Golgi apparatus, mitochondria, and neutral-red bodies are morphologically distinct structures in the cells of the salivary glands of the Chironomus larva.
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  • 12
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982) 
    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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  • 13
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 87-100 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In an attempt to determine the role in the immune responses of the typhlosole, a hematopoietic tissue along the ventral wall of the larval lamprey Lampetra reissneri, scanning and transmission electron microscopic observations were made on ammocoetes hyperimmunized with sheep red blood cells. Besides including the cells of the erythrocyte series, this tissue also contained the following leucocytes forming an amorphous parenchyma: the cells of the granulocyte series, the most predominant cell type, possessing a markedly lobed nucleus and membrane-bounded granules of various sizes; the macrophages possessing primary and secondary lysosomes and long lamellipodia on the cell surface; the lymphocytes of a large nucleocytoplasmic ratio with a number of long, spiky microvilli, constituting a major type of rosette-forming (antigen-binding) cells; and the plasma cells possessing highly extended cisternae of rough endoplasmic reticula that are characteristic of the higher vertebrates. The immunoperoxidase technique, which employs rabbit antibodies against lamprey immunoglobulin, proved that these plasma cells do contain immunoglobulin. These results strongly indicate that the typhlosole of the larval lamprey, besides functioning as a hematopoietic tissue, is actively involved in the antibody responses. It is also stressed that the plasma cell occurs in the most primitive vertebrates as an immunologically competent cell.
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  • 14
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 129-135 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The regenerative capacity of limbs was investigated by amputation of limbs at the zeugopodium in postmetamorphic froglets and adults of various sizes in four species of Japanese frogs, all of which showed some regeneration at these ages. In Hyla arborea japonica and Rana brevipoda porosa most young froglets regenerated their limbs well; however, the rate of regeneration decreased with the age of amputation, and the limb became nonregenerative in adults. Limbs of adults in Rana rugosa and R. japonica, on the other hand, exhibited good regeneration. All of the regenerates in the four species were heteromorphic, consisting histologically of well-developed cartilaginous rods surronded by connective tissue and skin. Limited development of muscle was appartment in regenerates of the three ranid species. The relations between body size, innervation of limbs, and regenerative capacity are discussed.
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  • 15
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    Journal of Morphology 174 (1982), S. 283-312 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure and mechanism involved in jaw movements are described for an inertial high-speed suction feeding fish, Chaetodon miliaris. Jaw biomechanics were studied by (1) manipulation of live and fresh-killed specimens, (2) electrical muscle stimulation of anesthetized live specimens, (3) connective tissue severance experiments of fresh-killed and live anesthetized specimens, and (4) cine photography of live unimpaired and surgically impaired specimens.Three couplings appear to be involved in jaw opening: a levator operculi-opercular-interopercular-mandible coupling; and epaxial complex and/or hypaxial/sternohyoideus complex-hyoid apparatus-uncontracted protractor hyoideus-mandible coupling. Jaw opening, protrusion, closing of the protruded mouth, and jaw retraction occur in 60-110 msec. Jaw protrusion coincides with mandible depression during opening of the mouth. Closure of the protruded mouth is apparently the result of contractions of pars A1 and A2 of the adductor mandibulae muscle. Pars A3 and Aw may induce retraction of the jaws in the closed-protruded state. Jaw closure in the retracted, nonprotruded state may involve all branches of the adductor mandibulae.The importance of these findings is discussed in light of previous studies as are some proposed functions of jaw protrusion in this species.
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  • 16
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    Journal of Morphology 174 (1982), S. 41-56 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have studied the comparative anatomy of arterial plexuses (retia mirabilia) related to supply of the central nervous system in two closely related species of toothed whales - narwhal (Monodon monoceros) and beluga Delphinaterus leucas). In both species, retia originate from major vessels in the neck, thorax, and lumbar regions, then extend into the neural canal and cranium to supply the spinal cord and brain. The system generally consists of arteries embedded in á matrix of fatty connective tissue. Constituent vessels are only occasionally reated to veins or venous sinuses. Though retial anatomy is similar in the two species, there are two related features that appear species specific: (1) amount of retia originating from the supreme intercostal arteries and (2) thoracic retial size. Both are larger in the narwhal, as are values for hematocrit and hemoglobin concentration, which, in this study, we use as indices of diving ability. Our data are consistent with the hypothesis that the retia are in some way linked to diving ability. The nature of this link is not known; however, we discuss our results in the context of the most popular hyotheses of retial function.
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  • 17
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    Journal of Morphology 174 (1982), S. 141-147 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The reduced bone resorption characteristic of osteopetrosis is accompanied in the incisors-absent (ia) rat mutation by a significant increase in osteoclasts of inactive (mutant) phenotype. Restoration of bone resorption in ia rats by transfer of spleen cells from normal littermates is preceded by a transformation of osteoclasts from mutant to normal phenotype.In this investigation the proportions of osteoclasts of normal phenotype have been determined by light microscopy in untreated ia and normal rats and in ia rats treated with various cell populations from normal rats. Significant increases in numbers of osteoclasts of normal phenotype were seen in the mutant skeleton soon after cell treatments that eventually restored bone resorption and cured the disease. No changes in osteoclast phenotype were seen after cell transfers that did not cure the disease.These data establish transformation of osteoclast phenotype as an early event in the recovery from osteopetrosis and suggest that determination of osteoclast phenotype is a reliable predictor of the success of normal cell populations to restore bone resorption in this mutation.
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  • 18
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    Journal of Morphology 174 (1982), S. 169-184 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gross morphology, histology, and ultrastructure of Liolaemus gravenhorsti gonads prior to and after differntiation are described. Special emphasis has been given to characterization and changes of the germ cell line throughout intrauterine development and 3 days postpartum.During the pregonadal stage, the primordial germ cell migrates toward gonadal rudiments by way of the mesenchyme. These cells can easily be identified by their great size, voluminous and lobulated nucleus, great quantities of yolk platelets, microtubules, and numerous lipid inclusions. In the undifferentiated gonad, the germ cells (type 1 gonocytes) have an ovoid or spherical shape and autodigestion of yolk platelets, great development of Golgi complex, and mitochondrial aggregation, though fewer liposomes, pseudopodes, and microtubules were noted. Concomitantly with the beginning of mitosis, a third type of germ cell appears, the type 2 gonocytes, which are smaller, with poorly defined membranous systems in various degrees of involution. The seminiferous cords are organized when somatic cells of the medullar portion of the gonad surround type 1 gonocytes. Germinal cells are centrally localized in the cords. Near birth many gonocytes migrate toward the basal lamina of cords and differentiate into spherical prespermatogonia, with few organoids. Sertoli cells eparate them from the basal lamina. In advanced pregnancy, Leyding cells become numerous with morphology typical of androgen-producing cells.
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  • 19
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    Journal of Morphology 174 (1982), S. 217-236 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A forebrain atlas and stereotaxic neurosurgical techniques were developed for use in anatomical and behavioral experiments on the green anolis lizard (Anolis carolinensis). Green anoles are convenient and robust experimental subjects with a rich behavioral repertoire, the social components of which are partly under hormonal control.The technique and atlas were devised to conduct neuroethological investigations of the effect of lesions on species-typical display behavior. The atlas consists of 12 transverse sections from an average size adult male. The figures (4-15) are based on Nissl material and supplemented with fiber-stained material from adjacent sections. They appear at the end of the article. Limitations on the accuracy of stereotaxic coordinates are discussed and tables of correlative nomenclature for principal telencephalic and diencephalic nuclei are provided.
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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: Dissection and a variety of absorption and fluorescent cytochemical methods have demonstrated that Antrodiaetus unicolor females have only one type of silk gland and spigot and, consequently, the simplest silk production system of any spider yet investigated histochemically. The small spherical to pear-shaped glands are grouped into four clusters, each cluster serving one of the four spinnerets. The spigots are long, slender, and slightly bent distally. Although all gland cells are structurally similar, each gland simultaneously produces two different secretory products, the secretion of the distal hemisphere being rich in basic protein and sulfhydryl groups, and the proximal hemisphere secretion being an acidic protein containing a high concentration of histochemically demonstrable C-terminal carboxyl groups. The two products remain segregated as they pass through the duct, where the acidic protein forms a thin outer layer around a core of basic protein. It is suggested that this segregation may persist in the silk strand after it exits from the spigot and that the outer acidic protein may be an adhesive agent.
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  • 21
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    Journal of Morphology 174 (1982), S. 335-348 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The organization of the vestibulolateral lobe of the cerebellum is described in electroreceptive and closely related nonelectroreceptive teleost fishes. The vestibulolateral lobe includes an eminentia granularis and a lobus caudalis. The eminentia granularis is a lateral line-recipient, granule cell zone which in weakly electric fish (i.e., electroreceptive fish with an electric organ) has anterior and posterior divisions associated respectively with a mechanoreceptive medial medullary nucles and an electroreceptive lateral line lobe. A lobus caudalis includes a separate granule cell zone - the pars medialis, a molecular layer, and large Purkinje-like cells. Compared with weakly electric mormyrids, the pars medialis is hypertrophied in weakly electric gymnotoids and electroreceptive silurids. However, the pars medialis is also hypertrophied in nonelectroreceptive teleosts, suggesting it is a granule cell zone not associated with electroreception and perhaps the lateral line system.
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  • 22
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    Journal of Morphology 172 (1982), S. 313-322 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the fat body of the higher termite king and queen has been studied both in species with (Macrotermes bellicosus, M. subhyalinus) and without (Cubitermes fungifaber) tracheal rosettes. There is a very pronounced sexual dimorphism. The adipocytes of the queen are highly specialized for protein synthesis and secretion; they store only a small quantity of reserves. The adipocytes of the king are not specialized in protein synthesis, but accumulate large amounts of reserve substances. The previously proposed different functions of the termite queen's fat body are discussed; it appears to be mainly concerned with vitellogenesis.
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  • 23
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    Journal of Morphology 173 (1982), S. 1-16 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning and transmission electron microscopy, together with dissection and light microscopy, have produced heretofore unavailable structural detail of the ovary of Fundulus heteroclitus. Structural and functional interrelationships among developing follicles and other histological elements, particularly as they might relate to vascularization of follicles, oocyte development, and ovulation, are described and discussed. Mature eggs, ovulated into the ovarian lumen, accumulate in the posterior “ovisac” region of the ovary prior to oviposition. This “ovisac” region is thin-walled and apparently nongerminal. The temporary retention of ovulated eggs permits cyclical oviposition even though oogenesis and ovulation are asynchronous. The histological differences between the ovisac and the anterior ovigerous of the ovary are described. The lumenal epithelium of the ovisac displays a localized population of unusual cells with long cytoplasmic extensions. The ultrastructure of these cells suggests that they might function in the transport of ovulated eggs into the oviduct and/or in secreting the substance (“jelly”) which forms the surface coat of extruded eggs.
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  • 24
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    Journal of Morphology 173 (1982), S. 43-72 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A scanning electron microscopy study was made of the male setiferous sex patches and analogous structures in 11 families of Coleoptera (Anthribidae, Bruchidae, Ciidae, Cleridae, Coccinellidae, Dermestidae, Leiodidae, Ptinidae, Staphylinidae, Tenebrionidae, and Ostomatidae). These secondary sexual characters appear to have several features in common including relatively long, often ridged, setae, cuticular ducts (frequently cribriform pore plates), and the production of a secretion. It is suggested that these structures may all be concerned with the production, release, and dissemination of pheromones.
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  • 25
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    Journal of Morphology 173 (1982) 
    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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  • 26
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    Journal of Morphology 173 (1982), S. 159-177 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Single esophageal and paired cheliceral, palpal, pedal (I-IV), and opisthosomal nerves enter the synganglion and form specific neuropilar ganglia. The ganglia are integrated by a complex series of commissures and connectives. Eighteen paraldehyde-fuchsin-positive neurosecretory regions, which vary greatly in size and amount of granular neurosecretory material, are each associated (one or more) with neuropilar ganglia. Presumably transport of neurosecretory materials to target tissues occurs through axonal pathways, perineurial-neural lamella associations, and the neurohemal retrocerebral organ complex.
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  • 27
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    Journal of Morphology 49 (1930), S. 153-221 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A study is made of the morphological types of the second, third, and fourth interdigital patterns of the human palm and their differential occurrence as a basis for determining the morphological significance of the digital triradii and main lines, which are the final remnants of the pattern boundaries. Certain types of patterns show a large preponderance, with a correspondingly large percentage of a certain morphological value for each digital triradius, although other morphological possibilities than the usual one are discovered in each case. Correlated combinations of rare patterns are presented and their hereditary nature discussed.
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  • 28
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    Journal of Morphology 49 (1930), S. 251-275 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Intravitam stains were used to determine the functions of several organs in two species of nemas (Rhabditis strongyloides and Rhabditis elongata). The organs were also studied in section. From the results obtained it is concluded that the amphids are not excretory in function, but more probably sensory, for definite connections were observed to extend to the nerve ring. No migratory cells, such as those described by Stefanski, were seen.The phasmids stained with all intravitam stains used. but were never observed to secrete. It seems doubtful that they serve as excretory organs.The excretory system was seen to consist of a typical X system. Actual excretion was observed. Deirids were seen for the first time in both species. Oesophageal glands were also described. A study was made of the structure of the intestinal cells, rectal glands, and anal muscles. Attention was called to the fact that there are two kinds of ejaculatory glands, one of which probably serves as a ‘cement gland,’ while the function of the other is still in doubt.
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  • 29
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    Journal of Morphology 49 (1930), S. 355-383 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The breeding season of Bugula flabellata extends from June 10th to November 15th. The young embryos develop in brood pouches (ovicells) and are finally expelled from the colony as swimming embryos. They come from the colonies at dawn or early morning. After a free-swimming period of four to six hours, each larva becomes attached and after a profound metamorphosis which involves the loss of larval organs, it develops into the bryozoan colony by budding.The larvae at first are positive to light, but become negative before attachment. Their behavior is described in detail and the mode of attachment is explained.After the larva has become attached a period of rapid growth by budding ensues. The rate of growth is given in a table in which it is shown that the first individual of the colony is completed in two days and that a new series of buds is formed every two days. There are eight or ten individuals after one week and over a hundred in two weeks. In one month the colony is half-grown and becomes sexually mature. A colony becomes senescent in three months, when it measures 112 to 134 inches in diameter.Younger colonies hibernate successfully and resume growth in early May, when new polypides are formed.
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  • 30
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The germ cells in human embryonic ovaries arise by proliferations from the germinal epithelium. These cells pass through the early maturation phases, including synizesis, beginning at about the third month. Four distinct periods may be distinguished in ovogenesis, each having its own peculiar characteristics: the early embryonic period from seven weeks to three months, the middle embryonic period from three to five months, the late embryonic period from five to seven months, and the adult period. The early embryonic period shows only growth and multiplicative phases; the middle embryonic period is distinguished by maturation phases, among which phases are interpolated which do not appear elsewhere in the species; the late embryonic period is charcterized by phases similar to those of the adult male germ cells, and the adult period by the omission of early maturation phases preliminary to the maturation divisions.
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  • 31
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    Journal of Morphology 50 (1930) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 32
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The first of a series of studies on the comparative histology of the digestive tubes of fishes selected, on the basis of their feeding habits, from the teleost group: a study of the microscopic anatomy of the digestive tube of a predaceous teleost, the sea bass (Centropristes striatus (L.)). Based on studies of sections, with details of gross anatomy from both fresh and preserved material. Includes a short survey of previous work. Deals with the histology of the various regions of the tract, their tunics and tissues, together with details of cell structure and arrangement. Approach is made from the physiological side, with particular reference to the adaptation of histological elements to functional activity. Parts treated in detail are esophagus, cardiac and pyloric limbs of the stomach, intestine, and pyloric caeca. Particular stress is laid on the histological structure and arrangement of the tunica mucosa, especially in relation to digestion and absorption. Topics given particular emphasis are: condition of mucosal folds with reference to the amount of food present in the lumen; transformation between adjacent epithelia of different types; structure of cardiac and pyloric glands; origin and differentiation of intestinal goblet cells; comparisons between histology of pyloric caeca and that of adjacent intestine, together with general conditions found in the caecal mucosa.
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  • 33
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    Journal of Morphology 49 (1930) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 34
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    Journal of Morphology 49 (1930), S. 139-151 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In Trichamoeba sp two types of inclusions are recognized on the basis of reaction to vital dyes and tomethods of osmic and silver impregnation. Globular inclusions, which are stained selectively with neutral red, may be blackened under direct observation by exposure to osmic vapor in hanging-drop preparations and demonstrated by osmic and silver impregnation. Rod-like and granular mitochondria, stainable vitally with Janus green, may be distinguished from the neutral-red globules in preparations stained with a mixture of Janus green and neutral red, and are demonstrated by Regaud's chondriosome method.
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  • 35
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spining in Galleria begins shortly after hatching and continues throughout larval life. The gland cells secrete continuously, irrespective of the act of spinning.The nucleus plays a direct and an importnat rôle in silk secretion by the migration of nucleoli into the cytoplasm, where they enlarge and synthesize a fatty material in the center; the fatty material is transformed into a non-soluble basophllic substance, which then changes into the secretory product in its final form. The processes of converting the fat into non-soluble substance and of converting the latter into the secretory product progress inwardly from the periphery of each secretory body. The secretory bodies or masses of secretory material break up into smaller and smaller masses and eventually into a fine dispersed state before their entrance into the lumen of the gland.The mitochondria are granular in the cells of the conductive portion and filamentous in those of the reservoir and secretory portions of the gland. In the secretory portion they are orientated with the long axis toward the gland lumen. Their rǒle in silk secretion is negligible or at most a minor one.The Golgi apparatus is in the form of discrete ring- and half-ring-shaped bodies and remains so during all stages of secretion. If it plays any rǒle in silk secretion, the fact has not been detected by the author.
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  • 36
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    Journal of Morphology 50 (1930), S. 453-473 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ovaries of adult albino rats were studied, the following phases being considered: Eleven to twenty and one-half days pregnant, shortly after fertilization, oestrus, not pregnant, young sterile, old, and senile. Some new ova are produced from the germinal epithelium during pregnancy and oestrus, but it is in the ovaries of non-pregnant animals between oestrous periods that the germinal epithelium is most active. There can be no question of the formation of new ova during adult life, for there is a correlation between the activity of the germinal epithelium and the number of oocytes and young follicles present in ovaries. Also one can trace the origin of ova in the surface and follow their transformation and movement into the ovary proper. In some sterile young animals little new formation took place, in others a good deal. In old and senile animals the germinal epithelium continued to be active, especially in producing ingrowing cords of cells, but frequently these were anovular. The germinal epithelium may form different types of cells by ingrowth: ova, follicle cells, and interstitial cells, but the formation of anovular follicles at one period does not prevent a later production of normal ova and follicles.Some new ova are produced from the germinal epithelium of ovaries during pregnancy and oestrus, but it is in the ovaries of non-pregnant animals between oestrous periods that the germinal epithelium is most active. There can be no question of the formation of new ova during adult life, for there is a correlation between the activity of the germinal epithelium and the number of oocytes and young follicles present in ovaries. In some sterile young animals little new formation took place; in others, a good deal. In old and senile animals the germinal epithelium continued to be active, especially in producing ingrowing cords of cells, but frequently these were anovular. The germinal epithelium may produce different types of cells by ingrowths - ova, follicle cells, and interstitial cells - but the formation of anovular follicles at one period does not prevent a later production of normal ova.
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  • 37
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: A study of the cytological changes occurring in the larval oenocytes of Galerucella nymphaeae Linn., correlating those changes with the molting cycles. Preceding each larval molt, vacuoles, apparently of nuclear origin, are found in the cytoplasm from which they are eliminated at the time of the molt. The accumulation of vacuoles is not so striking at the times of pupation and the emergence of the imago, but occurs nevertheless. Beginning with pupation or just previous to it, the larval oenocytes seemingly undergo a process of deterioration, decreasing in size and presenting a ragged appearance.The fat-cells are closely associated morphologically with the larval oenocytes, and it seems that there is a probable physiological relationship also, since the fat-cells undergo a series of changes at the same time the oenocytes are exhibiting their cyclic behavior. Furthermore, it has been observed that in many instances there is a greater accumulation of vacuoles in that part of the cytoplasm of the oenocytes which is adjacent to the fat-cells than elsewhere.
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  • 38
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    Journal of Morphology 49 (1930), S. 415-453 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The male and female germ cells of Polygra appressa were found occurring together in the acini from the time the snails were 5 mm. in width onward, and their development traced backward to the gonial stage, in which the aspect of the female cells, present in small numbers in the acinus wall, and the male cells, in greater numbers in the lumen, seems identical.In oocytes, differentiation involves the enormous increase in volume of cell, nucleus, and plasmosome; the appearance of yolk and of a secondary nucleolus attached to the first one, and, in some cells, various other nucleoli, attached to the chromosomes. Meanwhile the chromosomes become diffuse and spread into the interior of the nucleus, finally condensing again on the periphery. The employment of various technical methods produced interesting variations in the aspect of oocyte chromatin and nucleoli.The appearance of the Nebenkern in spermatocytes during the growth period was noted, but no indication of its presence discovered in oocytes until the fairly late growth period.The chromosome forms were noted in spermatogonia, first spermatocytes and oocytes, and their numbers found to be 61 63, 31, and 31, respectively, but no clear dividing oogonia were found, on which similar observations could be made.
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  • 39
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    Journal of Morphology 50 (1930), S. 71-126 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An extensive survey of the anatomy of the endolymphatic organ (i.e., endolymphatic sac and duct) has been made on thirty-four species of amphibians.1The histological structure is similar throughout the group; the sac being formed of cubical cells, which grade into the columnar cells of the duct. A part or the whole of the duct is formed of peculiar ‘ependyma-like’ cells.2The organ typically arises from the sacculus, extends to the endolymphatic foramen by which it enters the endocranial cavity. Here the sac-like expansion of the organ lies in the extradural space.3Six morphological types of endolymphatic organ may be recognized in the Amphibia.4The development of the endolymphatic organ of four of these types has been followed. The structure in each case may be considered to have reached its definitive condition at the time of metamorphosis.5The types of sac structure cannot be readily correlated with any habit of the animals possessing them.6A discussion is given of the homology, comparative morphology, and function of the organ throughout vertebrates.
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  • 40
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    Journal of Morphology 50 (1930), S. 259-293 
    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 development of the ear of the common dogfish from the 3.5-mm. stage to the adult, with a brief review of the literature and comparison with related forms.The study includes the following topics: First indications of vesicles. The beginning of specialization. The separation of component structures. The sensory epithelium. The structure of the adult ear, including a description of the sensory areas, the innervation, the lagena.The position of the future canals is first indicated in 15- to 20-mm. stages. The sacculus and utriculus were first noted in the 22-mm. stage. Complete separation of the canals, the sacculus, utriculus, the recessus utriculus, and the lagena has occurred by the time the 33-mm. stage is reached. Definite innervation of the ampullae is found at this stage.The article contains twenty-seven figures; eight of them are drawings made from wax reconstructions of various stages.
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  • 41
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    Journal of Morphology 50 (1930), S. 361-392 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This ontogenetic study shows the following facts: (1) the presence of a vidian artery homologous with that of reptiles, which serves visceral elements of the jaw; (2) there exists a transitory occipital artery arising from the stapedial which contributes to the vascular supply of the occipital region; (3) the presence of a transitory fifth arch intimately associated with the sixth arch; (4) there is evidence of at least two presegmental branches of the aorta; (5) in the development of the adult pulmonary stem the right artery forms very little of the common vessel; (6) a single cephalobrachial trunk forms the culmination of arch development; (7) arterial development of the head and neck falls into three phases: (a) a temporary arterial pattern designed to carry nutriment to primitive head structures, (b) a plan of arterial distribution adapted to supply the rapidly forming cartilage and muscle of the jaws, and, (c) a readjustment period when the arterial plan is readjusted due to the increased heteronomy of the head.
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  • 42
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    Journal of Morphology 50 (1930), S. 413-451 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The process of ‘chromatin diminution’ may be said to be a casting off of chromatic material from the chromosomes earlier or later in the course of mitosis. A study of the phenomenon as it occurs in Ephestia and Ascaris shows it to be comparable in only the broadest and most general sense.In Ephestia the diminution substance is not formed in the nucleus, but is due to a later differentiation of the chromosomes long after their discharge from the nucleus. This can be made apparent by the use of differential stains and by other methods.In Ascaris diminution is found not to occur until the third cleavage, and then in all three cells that are destined to be somatic. The diminution process in this instance is apparently comparable to the casting out of residual substance which occurs when the nuclear vesicle breaks down in other cells.
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  • 43
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    Journal of Morphology 50 (1930), S. 517-525 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fertilized hen's eggs of known origin were incubated under predetermined, standardized, and uniform conditions of all physical factors except air, the composition of which in respect to the carbon dioxide and oxygen varied in each experiment. The growth and mortality of the embryo were studied daily, with, on an average, four observations.The experimental data show that the continuous exposure to about 0.4 per cent of carbon dioxide in the air of the incubator stimulated growth during the first part of embryonic life. A high content of carbon dioxide and at the same time a slightly reduced content of oxygen resulted in diminishing of the size and increasing of mortality of the embryo. The maximum combined proportions of these gases possible for growth of the embryo were about 22.0 and 16.3 per cent, respectively. A temporary exposure (twenty-four and forty-eight hours) to a large amount of carbon dioxide resulted in diminishing the size of the embryo without apparent deformities or increase of mortality.
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  • 44
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The events associated with premolt reformation of the cuticularized ductule in the underdeveloped (immature) branchial rosette glands, which are common in the gills of small (14-18 mm, total length) grass shrimp, are described and contrasted with the events of ductule reformation in the fully developed (mature) resette glands most common in larger shrimp. In immature rosette glands, two ciliary processes emerge from each of the component secretory cells and ascend into the basal luminal region of the old ductule. Subsequently a new ductule is formed around the old ductule, and the ciliary processes disappear, either because of degeneration or retraction. The transitory ciliary processes appear to prevent the old ductule from collapsing during the formation of a new ductule. Such transitory ciliary processes, however, are not found in association with premolt ductule reformation in the mature rosette glands; in their place are seen a number of microvilli-like cytoplasmic processes, which emanate from the apices of the secretory cells and from the channels of the central cell. These cytoplasmic processes in mature glands, like the ciliary processes in immature glands, are transitory and appear to prevent the collapse of the old ductule.Cytoplasmic processes comparable to those in mature glands, but relatively few in number and originating only from the secretory cells, are seen together with ciliary processes in some immature glands. The relative abundance of cytoplasmic processes in the mature glands, coupled with the observation that transitory ciliary processes occur in immature glands but not in mature glands, suggests that, during glandular maturation, transitory ciliary processes are replaced by transitory cytoplasmic processes.
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  • 45
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    Journal of Morphology 171 (1982), S. 123-136 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spermatozeugmata (sperm bundles lacking a distinct wall) from the spermathecae of Tubifex tubifex are composed of two different zones: an internal axial cylinder containing conventional spermatozoa and an external cortex composed of modified spermatozoa, tightly packed together. The conventional spermatozoa conform to the classical clitellate scheme: very long and thin with a complex acrosome, a filiform nucleus, small mitochondria, and a flagellum with Y links and β glycogen granules as accessory structures. The modified spermatozoa show “empty” acrosomes, degenerating nuclei, and tails which contain γ glycogen granules. The tails are helically wound around the spermatozeugma and are connected to each other by junctional complexes. The tips of the cortical tails are free and move with a metachronal wave. The presence of two sperm types in tubificids is discussed and a protective function for the modified cortical spermatozoa is proposed.
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  • 46
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    Journal of Morphology 171 (1982), S. 183-194 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The intraembryonic reticuloendothelial response to phenylhydrazine-induced hemolytic anemia was studied embryonic chicks (days 13-16) by light and electron microscopy and histochemical and biochemical assays for acid phosphatase. Phenylhydrazine was given on day 13 and tissue taken at 2, 5, and 10 h and at 1, 2, and 3 days after injections. The response varied in the three major reticuloendothelial organs. The spleen first demonstrated an increase in erythrophagocytosis that was accompanied by increased acid phosphatase levels. Erythrophagocytosis occurred primarily in the red pulp resulting in increased numbers of macrophages, increased size of macrophages, and retention of erythrocytes, which together combined to enlarge the spleens. By 2 days after phenylhydrazine injection, greatly enlarged macrophages began to migrate into the venous system, where some erythrophagocytosis continued to occur. The liver was also a major erythroclastic organ in which Kupffer cells became increasingly erythrophagocytic. However, erythrophagocytosis began later than in the spleen, and as measured by acid phosphatase levels, the liver was not as effective in removing damaged erythroid cells. Marrow erythrophagocytosis was only slightly enhanced; however, the marrow responded by increasing its production of red blood cells. Thus, the intraembryonic reticuloendothelial organs of the embryonic chick responded to phenylhydrazine-induced hemolytic anemia in much the same manner as might be expected of the adult bird.
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  • 47
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    Journal of Morphology 172 (1982), S. 5-22 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The siphuncle of the chambered nautilus (Nautilus macromphalus) is composed of a layer of columnar epithelial cells resting on a vascularized connective tissue base. The siphuncular epithelium taken from chambers that have not yet begun to be emptied of cameral liquid has a dense apical brush border. The great number of apical cell junctions (zonula adherens) compared to the number of nuclei suggests extensive interdigitation of these cells. The perinuclear cytoplasm of these preemptying cells is rich in rough endoplasmic reticulum. The siphuncular epithelium of both emptying and “old” siphuncle (which has already completed emptying its chamber) both show little rough endoplasmic reticulum but do contain extensive systems of mitochondria-lined infoldings of the basolateral plasma membranes. Active transport of NaCl into the extracellular space of this tubular system probably entrains the water transport involved in the chamber-emptying process. Both emptying and old siphuncular epithelium also show large basal infoldings (canaliculi) continuous with the hemocoel, which appear to be filled with hemocyanin. The apical cell junctions of emptying and old siphuncular epithelium contain septate desmosomes that may help to prevent back-flow of cameral liquid into the chambers.
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  • 48
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    Journal of Morphology 171 (1982), S. 41-67 
    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 exocrine rosette glands (called type A and type B), located in the gill axes of the grass shrimp Palaemonetes pugio, are described. The type A glands are embedded within the longitudinal median septum of the gill axes, whereas the type B glands typically project into the efferent hemolymph channels of the gill axes. Although both glands have certain common characteristics (i.e., a variable number of radially arranged secretory cells, a central intercalary cell, and a canal cell that forms the cuticular ductule leading to the branchial surface), they differ in the following respects. The type B gland is innervated, but the type A gland is not; axonal processes, containing both granular (ca. 900-1300 Å) and agranular (ca. 450-640 Å) vesicles, occur at a juncture between adjacent secretory cells and the central cell of the type B gland. The secretory cells of type A and type B glands differ in their synthetic potential and membrane specializations. These differences are more pronounced in well-developed, mature glands, most frequently encountered in larger (24-28 mm, total length) grass shrimp, than in the underdeveloped, immature glands that are most abundant in smaller (14-18 mm, total length) grass shrimp. Thus, in mature glands, the secretory cells of the type A rosette glands are characterized by extensive RER, abundant Golgi, and numerous secretory granules, whereas the secretory cells of the type B gland are characterized by extensively infolded and interdigitated basal plasmalemmas and by the presence of numerous mitochondria. In general, both types of glands exhibit increased secretory activity soon after ecdysis. The central and canal cells in both glands seem to have a role in the modification of the secreted materials. The possible functions assigned to the type A gland and the type B gland include phenol-oxidase secretion and osmoregulation, respectively.
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  • 49
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    Journal of Morphology 171 (1982), S. 89-117 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The events in the transformation of the intestine of the larval lamprey into the adult intestine were followed through the seven (1-7) stages of metamorphosis in anadromous Petromyzon marinus L. Light and electron-microscope observations demonstrated that the processes of degeneration, differentiation, and proliferation are involved in the transformation. In the anterior intestine, degeneration of cells and the extrusion of others into the lumen results in the disappearance of secretory (zymogen) cells and the decline in numbers of endocrine and ciliated cells. Larval absorptive cells, with a prominent brush border, are believed to dedifferentiate into unspecialized columnar cells with few microvilli. Degeneration and removal of cells occurs by both autophagy and heterography and cells extruded into the lumen in the anterior intestine are phagocytosed by epithelial cells of the posterior intestine. The loss of epithelial cells during transformation results in the folding and degradation of parts of the basal lamina and in an extensive widening of the lateral intercellular spaces in all parts of the intestine. As metamorphosis is a nontrophic period of the lamprey life cycle, the possible morphological effects of starvation on the intestinal epithelium are discussed.The development of longitudinal folds is a consequence of the events of metamorphic transformation of the intestinal mucosa. Although an interaction between the epithelium and the underlying tissues is believed to be importent, the actual mechanism of fold development is unknown.The intestinal epithelium of adult lampreys develops from surviving cells of the larval (primary) epithelium. Unlike the situation in amphibians, there does not appear to be a group (nest) of undifferentiated larval cells which differentiate into the adult (secondary) epithelium. Instead, in lampreys, columnar cells that persist through the degradative processes seem to be the source of absorptive and ciliated cells and probably are responsible for mucous and secretory cells.Preliminary observations indicate that the intestinal epithelium of feeding adults is specialized into an anterior region which liberates a secretion, absorbs lipid, and possesses the machinery for ion transport. A posterior region absorbs lipid, secretes mucus, and likely is involved in some protein absorption.
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  • 50
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    Journal of Morphology 171 (1982), S. 159-181 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The octavolateralis area of actinopterygian fishes can be subdivided into a dorsal lateralis area composed of first-order lateral line nuclei, and a ventral octavus area composed of nuclei receiving first-order input from the eighth nerve. Three patterns of organization of the lateralis area are recognized in the present study. The organization of this area in polypteriforms and chondrosteans is similar to that in chondrichthyans. On the basis of recent studies in chondrichthyans (McCready and Boord, '76; Boord and Campbell, '77; Bodznick and Northcutt, '80), it is hypothesized that this pattern reflects the subdivision of the lateral line system into mechanoreceptive and electroreceptive portions. As petromyzontid agnathans also share this pattern of organization, it is hypothesized that they are elecroreceptive. The lateralis area of holosteans and nonelectroreceptive teleosts exhibits a second organizational pattern that is hypothesized to reflect the loss of the electroreceptive portion of the lateral line system; it is suggested that electroreception was lost sometime between the chondrostean and teleostean radiations. Each group of electroreceptive teleosts is believed to have evolved electroreception independently (Bullock, '74), a situation that is reflected centrally by a third organizational pattern within the lateralis area, which is distinctly different from that of early radiations of electroreceptive fishes.The octavus area of actinopterygians exhibits two patterns of organization-that of polypteriforms, chondrosteans, and holosteans, and that of teleosts. The functional significance of these patterns has yet to be elucidated.
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    Journal of Morphology 171 (1982), S. 225-243 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During initial stages of oogenesis, many nucleoli are adpressed to the inner membrane of the nuclear envelope. Small nucleolar fragments appear to traverse the pores of the nuclear envelope and accumulate in the perinuclear ooplasm as fibrogranular bodies. Mitochondria become closely associated with some of the fibrogranular bodies. In addition to ribosomes and polyribosomes that are present in small oocytes, lamellae of rough-surfaced endoplasmic reticulum (rER) increase greatly in number during early stages of differentiation. Some individual lamellae are attached at their ends to the outer membrane of the nuclear envelope. Many parallel lamellae of rER are then encountered as well as numerous circular profiles consisting of concentric loops of rER. Soon after the differentiation of the extensive system of rER, lipid droplets or spheres appear in the ooplasm and they are initially surrounded by many circular, concentric lamellae of rER. Initially, the number of concentric lamellae of rER surrounding a lipid droplet may vary from less than a dozen to more than two dozen. During middle and late phases of vitellogenesis, most of the lipid spheres that comprise the most numerous and significant component of the yolk are surrounded by only one or two concentric lamellae of rER (in some cases the lamellae are part rough-surfaced and part smooth-surfaced). In addition, annulate lamellae are then observed to be associated with a portion of the lipid droplet surface. The number of annulate lamellae that extend focally from the lipid sphere distally into the cytoplasm is variable; often two or three to more than a dozen lamellae. Small granules, many of which range from 6 to 12 nm and thin fibrils (approximately 2-3 nm in width) may be associated with the annulate lamellae. In addition, polyribosomes frequently appear to be continuous with the pore-associated material of the annulate lamellae. The ends of some annulate lamellae may extend as lamellae of the rER. The morphologic relationships and relationships and variations observed between the lipid droplets, rER, annulate lamellae, and polyribosomes during lipidogenesis in this oocyte are interpreted to support a recent hypothesis (Kessel, 1981a,b) that the pores of annulate lamellae may be involved in some manner with the processing of ribosomal subunits or precursors into functioning polyribosomes, and that their appearance in specific association with the surface of many lipid spheres and rER in the oocyte late in vitellogenesis may be related to the formation of additional functional polyribosomes necessary to complete the final synthesis of many lipid droplets that are present in the ooplasm of the full-grown oocyte.
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    Journal of Morphology 173 (1982), S. 119-128 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using transmission electron microscopy of thin sections we have examined neuronal concentrations at hypostome-tentacle junctions in Hydra littoralis. A total of 194 ganglion cells were counted in 587 serial thin sections of a single hypostome-tentacle junction. We found two distinct types of ganglion cells: those with and those lacking stereocilia. The majority of the neurons observed lacked stereocilia; in a single hypostome-tentacle junction only 37% of the ganglion cells possessed a kinocilium surrounded by rodlike stereocilia. Most of the ganglion cells (55%) were clustered together in the oral or upper epidermis of the hypostome-tentacle junction: Nineteen percent were in the lateral and 26% in the aboral or lower epidermis. The two types of ganglion cells did not differ significantly in their distribution. Both types of ganglion cell had synaptic contacts with other neurons and with epitheliomuscular cells. More than 85% of the neuroneuronal and 61% of the neuroepitheliomuscular cell synapses were located in the oral epidermis of a hypostome-tentacle junction. In addition, two-way chemical synapses and a gap junction between neurons were observed at hypostome-tentacle junctions. Our morphological evidence of synaptic connectivity in neuronal clusters at hypostome-tentacle junctions suggests that primitive ganglia are present in Hydra.
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  • 53
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    Journal of Morphology 173 (1982), S. 179-184 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ventral bars, cartilaginous projections from the ventral aspect of the synsacrum that contact and form a joint with the ilium, were found in all normal chick embryos of age E9 and older. Bars were absent in a number of embryos which had been paralyzed from age E4 by the use of the acetylcholine receptor blocker α-bungarotoxin. They were also absent in some embryos that had been paralyzed between ages E4 and E10 but allowed to move thereafter. The bars, already formed, remained present in a third group of embryos in which paralysis was initiated at age E10. Apparently, normal embryonic movements induce the formation of bars. In support of this conclusion is the observation that two of three embryos which had had their hindlimb buds amputated at age E3 lacked bars. In these embryos with amputations, the ilium was present at least in part, but the forces exerted on the region where the bars develop would have been greatly reduced because of the lack of hind limb musculature. It is concluded that the bars, which form part of the iliosynsacral joint, are induced epigenetically by normal embryonic movements.
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    Journal of Morphology 173 (1982), S. 101-118 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development of the crayfish retina was examined in embryos and first, second and third instars with both and light and electron microscope. Light microscopic observations indicate that differentiation begins at the posterior portion of the optic disc and progresses in an anterior direction. Development of screening pigment, dioptric elements, and rhabdoms all parallel this posterior to anterior gradient in the retina. Tracer studies in early embryos reveal that the retina is separated from the proximal neuropil regions by a distinct vascular space. This observation suggests that the source of new cells for the retina may not be the more proximal cell proliferation zone as previously indicated. It is proposed that mitotic activity within the retina and/or differentiation of cells from the anterior surface layer of the eye may be sources for addition of new cells to the retina. Proto-ommatidial clusters of seven retinula cells occur very early at the posterior region of the embryonic retina. Initially the receptor cells extend throughout the entire thickness of the retina, but later they withdraw from beneath the cornea to occupy only the proximal portion of the retina. Microvilli of the rhabdom arise from the centrally opposed membranes of the retinula cells in each cell cluster. Each new microvillus contains a core of fine filaments which extend out into the cytoplasm at its base. As development of the microvilli continues, the core filaments appear to be lost or altered, but the cytoplasmic bundles at the base of the microvilli persist.
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    Journal of Morphology 172 (1982), S. 139-149 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A model is presented to express how effectively animals increase the exposed surface area of their food by chewing. It includes a coefficient of masticatory effectiveness (E) the value of which increases with effectiveness of exposing new food surface area with each chew. Humans and other species of primates differ significantly in their values of E; among the nonhuman primates studies, Lemur catta has a higher coefficient than Lemur fulvus, and both have higher coefficients than either Varecia variegatus or Galago crassicaudatus argentatus. The differences among the coefficients to these prosimians are correlated with variations in specific features of the molar morphology.Of six lower molar shearing crests considered, the relative length of the post-metacristid correlates most highly with the coefficient of masticatory effectiveness for the prosimian species. Also, among comparable-sized prosimians, E correlates significantly with the absolute postmetacristid length. Both these findings indicate that the relative size of molar shearing crests is related significantly to how effectively an animal chews its food. There are also implications for an adaptation to a high-fiber diet.
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    Journal of Morphology 172 (1982), S. 193-207 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Freshly extruded spermatophores from the lobster, Homarus americanus, were examined using light microscopy and scanning and transmission electron microscopy. The tubular spermatophore is trifoil in shape with two lobes tapered laterally from a third lobe situated ventrally. It is comprised of sperm surrounded by three acellular investments: (1) a primary spermatophore layer, (2) an intermediate layer, and (3) an outer bounding layer. The sperm are packed into a continuous tube contained largely within the ventral lobe and are embedded in a matrix of moderate electron density. The primary spermatophore layer is uniformly thick around the sperm mass and contains at its peripheral margins both ring structures and crystals in an amorphous matrix. The intermediate layer is thicker dorsally than ventrally. Dense granules dominate the ventral half of the intermediate layer while inclusions populate the dorsal half; both react positively to the periodic acid-Schiff (PAS) technique. The innermost portion of the outer bounding layer is composed of parallel fibrils; a flocculent material is present peripherally. This flocculent substance is presumed to impart stickiness to freshly extruded spermatophores. These observations provide a basis for the future understanding of the mechanisms involved in long-term storage of sperm in spermatophores.
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    Journal of Morphology 172 (1982), S. 259-269 
    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 early embryonic development of Neomicropteryx nipponensis from oviposition to the formation of the inner layer. Newly laid eggs are covered with many hygroscopic, gelatinous masses. The chorion is composed of a porous, spongy exochorion of variable thickness and of a thin endochorion. The eggs have a very thin periplasm and contain large amounts of yolk made of proteid and fatty yolk droplets. The processes of maturation division, fertilization, and cleavage are similar to those commonly found in lepidopteran eggs. The blastoderm of Neomicropteryx is very thin in comparison with that of other lepidopteran eggs. The small circular germ disk is formed on the ventral egg surface. It then invaginates deeply into the yolk to form a sac-shaped germ rudiment. The formation of the germ rudiment and of the embryonic membranes resembles that of swift moths, Endoclita (suborder Monotrysia) and of the caddisfly, Stenopsyche (Trichoptera), but differs from that of ditrysian Lepidoptera. As in other lepidopteran insects, the formation of the inner layer begins after completion of the germ band, which has a bilobed protocephalon and a slender protocorm. Unlike the situation in most lepidopteran eggs, yolk segmentation does not occur in N. nipponensis. During formation of the germ band, hydropyle cells are formed in the dorso-posterior region of the serosa; these are here reported for the first time in the eggs of holometabolan insects.
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    Journal of Morphology 172 (1982), S. 299-312 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Analysis of the feeding apparatus of the stone crab, Menippe mercenaria (Brachyura, Xanthidae), has demonstrated that substantial internal and external morphological alterations occur at metamorphosis and suggests that the mastication of food shifts from the mandibles to the gastric mill at that time. These changes correspond to the changes in environment and diet that take place at metamorphosis, when the previously planktotrophic larvae begin benthic life.A detailed account of the structure and development of the mandibles is presented. The mandibles of all zoeal stages are similar: The incisor process has a series of teeth and denticles and the prominent molar process appears to be well adapted for grinding food. Megalopal mandibles are transitional but have the form that is typical of all subsequent stages: The expanded incisor process is rounded and toothless and the molar process is less prominent and has lost its grinding denticles. The cardiac stomach of the zoeal stages has no gastric mill; the medial and lateral teeth of the mill first appear in the megalopa.A very simple procedure is described for preparing larval mandibles for scanning electron microscopy using the molted exoskeletons from larval rearing experiments.
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    Journal of Morphology 172 (1982), S. 361-379 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the sensilla, and other structures, within the stylets and precibarium of Macrosteles fascifrons were examined by transmission and scanning electron microscopy. Precibarium is a new term, defined here, for the canal that precedes the cibarium inside the leafhopper head. Within the precibarium are found 20 chemosensilla and a previously undescribed structure, the precibarial valve. Twelve mechanosensilla, three in each stylet, are found within the maxillary and mandibular stylets. The relationship between all of these structures and feeding by the insect is detailed in a feeding mechanism hypothesis. It is concluded that leafhoppers (and probably all homopterans) utilize the precibarial chemosensilla alone for gustatory discrimination, the stylet sensilla for proprioception, and the precibarial valve for regulation of fluid uptake and compartmentalization of the sensilla.
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    Journal of Morphology 173 (1982), S. 29-33 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nephrons of carp (Cyprinus carpio) and goldfish (Carassius auratus) were examined histologically and also histochemically for enzymes. In both species the distal and collecting tubules have much wider lumens than do the other renal tubules; thus urine probably flows more slowly in these larger tubules. Enzyme histochemistry shows that epithelium of the neck and proximal and intermediate tubules respires anaerobically. whereas that of the distal and collecting tubules respires aerobically. The distribution of Na-K-ATPase in the distal and collecting tubules indicates that they also transport sodium actively. The slow flow of urine and the energy produced by aerobic metabolism probably increase the efficiency of active transport.
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    Journal of Morphology 171 (1982), S. 1-10 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of ovarian hormones on the activities of glucose-6-phosphatase and alkaline phosphatase in the vaginal epithelium was studied in immature and ovariectomized rats, using ultracytochemical techniques. Comparative studies were done on normal rats at the luteal phase and on day 14 of pregnancy.Various vaginal cells show different degrees of response to progesterone and diethylstilbestrol (DES) with regard to glucose-6-phosphatase activity. Intense glucose-6-phosphatase activity was observed in the cisternae of granular endoplasmic reticulum (rER), Golgi saccules and vesicles, and nuclear envelope of both basal cells and stromal cells of progesterone treated rats, whereas in the basal cells and stromal cells of DES-treated and control animals the enzyme was totally lacking. Detectable glucose-6-phosphatase activity was also observed, however, in the rER cisternae and Golgic complex of keratohyalin-secreting squamous intermediate cells of the vaginal epithelium of DES-treated rats. Alkaline phosphatase was observed in the plasma membranes of various cell types of vaginal epithelium in the normal, progesterone-, and DES-treated rats, Alkaline phosphatase was also found on the limiting membranes of secretory granules of mucocytes in animals at the luteal phase and during pregnancy. DES and progesterone in the doses used did not affect alkaline phosphatase activity in the rat vagina. Overall, progesterone enhances glucose-6-phosphatase activity in basal cells of the rat vagina prior to completion of mucification. Alkaline phosphatase was found in all cells involved in mucin secretion.
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    Journal of Morphology 171 (1982), S. 79-88 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution of the adrenaline and noradrenaline chromaffin cells in the adrenal glands of 10 members of the family Cordylidae have been examined. In the genus Gerrhosaurus, all the catecholamine cells lie on the surface of the adrenal gland, forming a continuous envelope of one or two layers of cells that mainly contain noradrenaline (NA). In the genus Platysaurus, the chromaffin envelope is intermittent. There are relatively large tracts of interspersed interrenal tissue containing some adrenaline cells (A). Islets of chromaffin cells are scattered between these interrenal tracts. In the genus Pseudocordylus and the genus Cordylus, the superficial chromaffin cells tend to gather into a multilayered dorsal mass, containing mainly NA cells. Inside the interrenal parenchyma, there are always numerous chromaffin islets, containing mainly A cells.
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    Journal of Morphology 171 (1982), S. 137-150 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Muscle spindles were studied histochemically in serial transverse sections of 42 cat tenussimus muscle specimens. Staining for myofibrillar adenosine triphosphatase was employed to identify nuclear bag1, nuclear bag2, and nuclear chain intrafusal muscle fibers. The nuclear chain fibers were further subdivided into three categories according to their polar length and the intensity of their staining for nicotinamide adenine dinucleotide tetrazolium reductase. A total of 430 spindle poles were surveyed. The mean spindle content of bag1, bag2, and chain fibers was established. The mean polar length of intrafusal fibers as well as that of the intracapsular and extracapsular spindle regions was determined. A cholinesterase (ChE) staining technique was used to demonstrate the termination sites of motor axons along intrafusal fibers. Two types of circumscribed ChE deposits, the “rim” and the “plate,” occurred on the fibers. The nuclear chain fibers usually carried both the ChE rims and plates, while most nuclear bag fibers displayed only the plates. The ChE plates were assessed in term of their appearance, staining intensity, length, and location along the fibers. The mean number of ChE plates found along the fibers was established for each of the various intrafusal fiber types.These histochemical observations are discussed with regard to the current concepts of cat spindle morphology and motor innervation. The results suggest a degree of predictability in the spindle fiber content and in the distribution of motor nerve terminals along intrafusal muscle fibers, at least in the tenuissimus muscle.
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    Journal of Morphology 171 (1982), S. 195-211 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Freshly harvested kidneys from New Zealand white rabbits, Sprague-Dawley white rats, rhesus monkeys, and transplant-quality human kidneys were used in this study. Minced renal cortical tissue blocks (〈2 mm3) were treated with 1 mM EDTA, 3% Triton X-100, 0.025% DNAse, and 4% sodium deoxycholate in an effort to remove all cellular elements and leave the extracellular matrix (ECM) intact. These preparations showed remarkable structural preservation and all components of the ECM, including basement membranes (BMs), maintained their in vivo histoarchitectural relationships. By light microscopy, at least four major BM types were recognizable, including Bowman's capsular BM (BCBM), tubular BM (TBM), glomerular BM (GBM), and peritubular capillary BM (PTCBM). Scanning electron microscopy demonstrated that, despite the lack of supporting interstitium, GBMs in human, monkey, and rat (and rabbit to a lesser degree) exhibit intrinsic structural rigidity such that their convoluted spheroidal shapes are maintained following cell removal. Transmission electron microscopy showed that major BM types are morphologically heterogeneous and vary markedly within and between species. Randomized measurements showed that isolated BM thicknesses (lamina densa only) compared favorably with those reported in cellular preparations. Mean thicknesses of GBMs were within normal ranges in all species with or without power transformations to reduce right-sided skew of distribution curves. In all species, thickness of BCBM 〉 TBM 〉 GGBM 〉 PTCBM. The striking morphologic heterogeneity of major BM types demonstrated in the acellular renal cortex is not surprising in view of recent biochemical analyses that show that BMs derived from different sources are compositionally disparate. We conclude that BMs should be evaluated and characterized individually and that morphologic definition of isolated BMs is necessary prior to further analysis.
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    Journal of Morphology 171 (1982), S. 259-281 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The aedeagal gland of male Tenebrio molitor consists of numerous acini containing several secretory units (organules) of three epithelial cells in series. The distal cortical cell and intermediate cell are secretory cells. Secretory products are passed into microvilli-lined extracellular reservoirs. From these storage areas products flow through minute canaliculi and into the efferent ductule. Canaliculi, cuticular trabeculae, and fibrillar material are characteristic features of the efferent ductules within the extracellular reservoirs of secretory cells. After passing from the secretory cells, the efferent ductule penetrates the basal ductule cell. The thin epicuticle that comprises the wall of the ductule is confluent with the epicuticle of the cuticular sheath forming the wall of the genital pocket. Secretory products flow from the cortical cell ductule into the intermediate cell and eventually empty into the genital pocket. A chemical reaction apparently takes place in the intermediate cell ductule, resulting in a frothy secretion product. When released from the ductule, this frothy product forms a foam-like layer that coats the inner wall of the genital pocket. Ultrastructural and probable functional aspects of this gland are described and discussed.
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    Journal of Morphology 171 (1982), S. 283-292 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: For years teeth of tetraodontoid fishes generally have been considered coalescent even though “coalescence,” which also is found in fishes of other families, has never been well defined. This paper deals with some aspects of coalescence of the teeth in tetraodontoids and attempts to define this condition. The sites of osteodentinogenesis and the mechanisms by which hard tissues are formed, reabsorbed, and abraded during feeding were analyzed from semiserial decalcified sections and from ground sections, as well as from autoradiographs of the premaxilla and dentary bones of Sphoeroides greeleyi. The observations reported here, taken together with other data we have obtained on members of the Tetraodontoidei, permit clear definitions of “tooth” and “supporting bone,” and consequently the structural meaning of coalescence. From these data we hypothesize how coalesced masticatory structures may have evolved in this group.
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    Journal of Morphology 171 (1982), S. 365-365 
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    Journal of Morphology 171 (1982), S. 321-353 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The masticatory pattern of Sphenodon punctatus, the sole remaining rhynchocephalian, now restricted to islands off the coast of New Zealand, has been analyzed by detailed anatomy, cinematography, cinefluoroscopy, and electromyography. Food reduction consists of a closing, crushing bite followed by a propalineal sliding of the dentary row between the maxillary and palatine ones. The large, fleshy tongue can be protruded to pick up small prey, and also plays a major role in prey manipulation. The rotational closing movement of the jaw, supporting the basic crushing movement, is induced by the main adductor musculature. It is followed by a propalineal anterior displacement relying heavily on the action of the M. pterygoideus. The fiber lengths of the several muscles reflect the extent of shortening. The most obvious modification appears in the M. pterygoideus, which contains a central slip of pinnately arranged short fibers that act a period different from that of the rest of the muscle; their action increases the power during the terminal portion of the propalineal phase. This also allows the animal to use its short teeth in an effective shearing bite that cuts fragments off large prey.The action of single cusped dentary teeth acting between the maxillary and palatine tooth rows provides a translational crushing-cutting action that may be an analog of the mammalian molar pattern. However, this strictly fore-aft slide does not incorporate capacity for later development of lateral movement.
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  • 69
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    Journal of Morphology 173 (1982), S. 185-195 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Force, velocity, and displacement properties of a muscle are determined in large part by its architectural design. The relative effect of muscle architecture on these physiological variables was studied by determining muscle weight, fiber length, average sarcomere length, and approximate angle of pinnation for 24 cat hind limb muscles. Muscle lengths ranged from 28.3 to 144 mm, whereas fiber lengths ranged from 8.4 to 105.5 mm. Generally, fiber to muscle length ratios were similar throughout a muscle. Estimated angles of pinnation of muscle fibers varied from 0 to 21° with most having an angle of less than 10°. The cross-sectional area of the knee extensors was similar to the knee flexors (16.43 vs. 16.83 cm2) whereas the cross-sectional area of the ankle extensors was more than six times greater than the ankle flexors (18.59 vs. 2.83 cm2). There was a 6.7-fold difference in the maximal force between muscles, when normalized to a constant weight, that could be attributed to architectural features. Rations of wet weight to predicted maximal tetanic tension for each muscle and group were calculated to compare the relative priority of muscle force versus muscle length-velocity for a given mass of muscle. These ratios varied from 0.4 to 4.84. The ratios suggest that velocity and/or displacement is a priority for the hamstrings, whereas force is a priority for the quadriceps and lower leg muscles. As much as a 12.6-fold difference in maximal velocity between muscles can be attributed to differences in fiber lengths. This can be compared to approximately a 2.5-fold difference in maximal velocity reported to occur as a result of biochemical (intrinsic) differences.
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  • 70
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    Notes: The surface receptors in Branchiobdella pentodonta consist of “sense buttons” prevalent on the prostomium, isolated sense cells all along the body of the animal, and free nerve endings. The “sense buttons” are uni- and multiciliated neurosensitive elements and supporting cells together with mucus glandular processes and muscle fibers. In the neurosensitive elements the cilia are always surrounded by cytoplasmic extroversion. The cytoplasm of the apical zone has abundant small dense granules, mitochondria, bands of tonofilaments, and microtubules. The cilium of uniciliated elements originates from three short roots. The highly vacuolated support cells surround the neurosensitive elements, separating them from each other. The “sense buttons” appear to be mechanoreceptors and chemoreceptors, and the isolated sense cells tactile mechanoreceptors, as are the free nerve endings. The surface receptors are compared with those of other Oligochaeta and Hirudinea.
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  • 71
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    Journal of Morphology 173 (1982), S. 259-278 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Some sea anemones possess structures called acrorhagi at the base of the tentacles. The acrorhagi are utilized solely for aggression. Acrorhagial aggression involves very exquisite intra- and interspecific recognition. This study examined acrorhagi and putative acrorhagial analogues or homologues in four species of sea anemone. The morphology and ultrastructure of tentacles, pseudoacrorhagi, column vesicles, and verrucae (adhesive column vesicles) differed from that of acrorhagi. Coral capitate tentacles and acrorhagi have different surface morphology, nematocysts, and functions. Besed on morphology, acrorhagi seem more likely to be homologous to tentacles than to verrucae.Acrorhagial nematocyst discharge and ectodermal peeling, the culmination of the response, were shown to require prior acrorhagial expansion in Anthopleura krebsi and Bunodosoma cavernata. A mechanical mechanism is suggested where- by distention of the acrorhagus opens a ciliary pit on the nematocyte surface and exposes the pit wall and microvilli, which may contain the chemoreceptors for the peeling process, including nematocyst discharge. A similar system may also be responsible for changing the threshold of nematocyst discharge in sea anemone tentacles. A case of possible neurosecretion in an anthozoan was also shown in this study.
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  • 72
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    Journal of Morphology 174 (1982) 
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  • 73
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    Journal of Morphology 174 (1982), S. 1-15 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of spermatogenesis is described for the marine calanoid copepod Labidocera aestiva. The mature spermatozoon is a slightly flattened, disc-shaped cell without a flagellum or an acrosome.Primary spermatocytes in first meiotic prophase are characterized by large nuclei showing progressive condensation of chromatin. The cytoplasm contains free ribosomes, numerous mitochondria, cytoplasmic vesicles, centrioles, and perinuclear nuage. Densely staining cisternae are associated with the nuage of pachytene and diplotene primary spermatocytes. This association may represent the temporary differentiation of an acrosome. Synaptonemal polycomplexes are frequently present in the nuclei of zygotene, pachytene, and diplotene primary spermatocytes. Many of the intercellular bridges which join the germ cells throughout spermatogenesis appear occluded by systems of transverse membranous cisternae. After the second meiotic telophase, spermatids are incorporated into nongerminal accessory cells that may facilitate the release of spermatids from the testis and regulate the rate of spermatogenesis by phagocytosis.During spermiogenesis the mitochondria become closely applied to the nuclear envelope, the nuclear envelope fragments and forms an elaborate membrane complex, a pentalaminar plasma membrane develops, and electron-dense material accumulates on the inner and outer surfaces of the plasma membrane in the mature spermatozoon.
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  • 74
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    Journal of Morphology 174 (1982), S. 79-94 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study examines the structure of mucosal glands in the walls of the hamster maxillary recess, compares the histochemical appearance of nasal glands to their sialic acid content, and determines the vulnerability of nasal glands to actinomycin toxicity. Observations were made on plastic-embedded tissue with light and transmission electron microscopes. Determinations of total sialic acid in mucosal samples were conducted with thiobarbituric acid. Experimental hamsters were administered 0.2 μg of actinomycin D (IP)/gm body weight/day for five days. Types of granules present in the lateral nasal gland (LNG) and glands of the maxillary recess (MRGs) include: 2.0 μm lightly basophilic, lightly electron-dense granules and 1.5 μm strongly basophilic, electron-dense granules in the same acinar cell type in both the LNG and MRGs; 1.5 μm metachromatic granules in some acinar cells of the LNG; 1.0 μm moderately electron-dense granules in cells of MRG ducts; and 0.7 μm electrondense granules in cells of LNG intercalated ducts. Acid glycoproteins, demonstrable by histochemistry, are present in the LNG but not in the MRGs. However, the total sialic acid content of tissues from MRG tissue is greater than that of other tissues measured. A minor number of LNG acini, those with metachromatic granules, have branching basal cytoplasmic projections. Many dark cells are present in striated ducts of the LNG. Histological alteration due to actinomycin-D toxicity, conspicuous in parotid salivary parenchyma, is greater in MRG than in LNG tissue.
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  • 75
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    Journal of Morphology 174 (1982), S. 121-131 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The head kidneys of adult Periophthalamus koelreuteri contain many functional glomerular nephorns which on the basis of this histochemical study, are indistinguishable from those of the typical opistonephros of marine teleosts. The anterior lobes resemble, in location and in the presence of intertubular erythropoeitic tissue, the pronephros in other species. The single nephron found there, however, does not differ significantly from the other nephrons of the head kidney. It is suggested, therefore, that the nephrons of the head kidney in this species are opisthonephric in origin.
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  • 76
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    Notes: The eyestalk of the astacideans Orconects limosus, Nephrops norvegicus, and Homarus gammarus, and the palinuran Palinurus vulgaris, was examined with an antiserum raised against purified crustacean hyperglycemic hormone (CHH) of the astacidean species Astacus leptodactylus. A distinct immunopositive reaction occurs in a group of neurosecretory cells in the medulla terminalis ganglionic X-organ (MTGX), in the MTGX-sinus gland tractus, and in a considerable part of the sinus gland. The immunoreactive sites in the eyestalk of the investigated species correspond to the site of production, storage, and release of the CHH. Preliminary investigations with this antiserum also indicate that a positive immunoreaction can be obtained in the eyestalk of other decapod crustaceans, for example, of the brachyuran Macropipus puber and the caridean Palaemon serratus.
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  • 77
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    Journal of Morphology 174 (1982), S. 197-205 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Shells from eggs of the tuatara (Sphenodon punctatus) are 0.2 mm thick and are composed of a layer of calcite and a multi-layered, fibrous shell membrane. Most of the calcareous layer is composed of roughly circular columns of crystalline material that extend deep into the shell membrane. The crystalline matrix of the columns is interwoven with fibers of the shell membrane except near the outer surface of the eggshell, where the calcareous material is more compact. Overlying the columns is a granular layer composed of blocks of crystalline material of random size, shape, and orientation. Disruption of this granular layer, perhaps through swelling of the eggs or as a result of environmental factors, gives the outer surface of the eggshell a coarse, weathered appearance. Removal of the calcareous material with a decalcifying agent shows that the outer surface of the shell membrane is composed of a meshwork of small fibers bound together by an amorphous matrix. No matrix was observed in inner layers of the shell membrane, and the fibers of these inner layers are arranged somewhat more regularly than the outer fibers. No structure comparable to the central cores of avian and certain chelonian eggs was observed in eggshells of the tuatara.
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  • 78
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    Journal of Morphology 174 (1982), S. 251-268 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Leukocytic organs of Amynthas diffringens are aggregations of leukocytes contained within a smooth muscle and stromal cell framework suspended in the coelom. Elongate processes of stromal cells subdivide each organ into numerous cell-filled compartments and are perforated by 130-nm pores that may permit the exchange of humoral substances between compartments, or between the organ and the surrounding coelomic fluid.We divide leukocytes within the organs into four morphotypes. Phagocytic leukocytes have many lysosomelike vesicles and may possess phagosomes. Mature types I, II, and III granulocytic leukocytes share certain features but are readily distinguished by cell shape and by the size, shape, and electron density of the cytoplasmic inclusions. Immature as well as mature phagocytes and granulocytes occur within these organs, suggesting that they are sites of leukocyte maturation and storage. Concentrations of leukocytes within the organs result in extensive cell to cell contact, especially within islets and tightly packed cords. Phagocytosis of cell debris occurs throughout the organs.Immature stages of the four morphotypes are difficult to distinguish even at high magnification, raising the possibility that they may originate from a common precursor. Our inability to observe mitoses or to detect lymphocytelike stem cells suggests that immature leukocytes migrate to the organs via coelomic fluid from as yet unidentified primary sites of production.
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  • 79
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    Journal of Morphology 49 (1930), S. 333-353 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The current view in mammals is that ova are formed in the embryo in large numbers and stored in the ovary as a reserve to be drawn on through adult life; they may persist for long periods ina latent condition, a few resuming active development at each recurring oestrous period; new ova are not and cannot be added.An alternative hypothesis has been presented by several authors: New ova are formed throughout life, from the embryonic period through the time of sexual maturity; each ovum so produced must at once begin its growth and development of die; long latency of oocytes and primary follicles is not possible and does not occur. There is a constant degeneration of most follicles, and only a few come to ovulation. A study of the albino rat presents evidence which is consistent with the second view and supports it more strongly that it does the older hypothesis. Similar evidence is found in other mammals. It seems probable that the newer hypothesis is the correct one, at least in some mammals; further investigation may show it to be of general application.
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  • 80
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    Journal of Morphology 49 (1930), S. 223-249 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the course of a hydrobiological survey of Monterey Bay, California, a series of pelagic organisms was taken at a depth of approximately 350 M., which appears to be a link connecting the Echiuroidea (Gephyrea armata) on the one hand and the polychaetes on the other. The range in body length is from 5 mm. to 27 mm.; and in an extended condition the anterior end of the body, with its palps and cirri, bears a close resemblance to a nereid. The supra-oesophageal ganglia and the ventral nerve cord, with eleven pairs of ganglia, are also strikingly annelidan in character. On the other hand, the spacious coelom, communicating with the exterior by a pair of anterior nephridia, allies it with the gephyreans. The same is likewise true of the gonad, which arises from the coelomic epithelium surrounding the genital vessel. The various systems are described in detail, and their resemblances to those of other annelids are indicated. This new species, Poeobius meseres, is made the representative of a new family, the Poeobiidae, which, provisionally at least, is included in the Echiuroidea.
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  • 81
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    Journal of Morphology 49 (1930), S. 277-331 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The entire ovary, including its germ cells, is produced by a local proliferation of peritoneal cells. The germ cells of the embryonic ovary grow, divide, become grouped into nests, pass through synaptic changes, and become primary follicles by three days after birth. At that time, growth of all the ova and follicles begins, and this results in a normal maturation, then a degeneration of all the ova by about thirty-two days after birth; few, if any, of the original germ cells remain after this degeneration. About twenty-three days after birth, there begins a great activity of the germinal epithelium in forming new ova, reaching its maximum between thirty-six and thirty-nine days, but continuing into the adult animal.The definitive ova of the adult are transformed peritoneal (germinal epithelial) cells formed anew during the late youthful and adult life. This occurs chiefly by a local enlargement of single germinal epithelial cells which become surounded by follicle cells and push into the ovary; there is also the production of ova from ingrowing cords of the surface layer of the ovary. The original germ cells pass through synapsis and other meiotic changes in late embryonic and early postnatal periods, but these all degenerate; synapsis cannot be distinguished later than three days after birth. But it is possible to follow, in young and adult ovaries, the transforming germinal epithelial cells into ova which pass through normal maturation and ovulation; therefore, these must be considered as true ova, which they are in fact, even though synapsis cannot be observed in their history.
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  • 82
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    Notes: A survey is made of the literature pertaining to lymph systems of the various groups of trematodes in which they occur, together with descriptions of the lymph systems in several forms not previously studied. The author reports the presence of a lymph system in two families, Cyclocoelidae and Heronimidae, which heretofore were considered to be without such organs, and the significance of this characteristic feature of certain trematodes is discussed as bearing on the problem of the evolution of monostomes, amphistomes, and other distomes. The gross morphology and the histology of the structural units of the system are described for Paramphistomum stunkardi, an amphistome from a fish, and for Diplodiscus temporatus, an amphistome from an amphibian, together with observations on the ramifications and structural components of the system in Cotylophoron cotylophorum. Various theoretical considerations concerning the development, function, and taxonomic and phylogenetic significance are treated on the basis of the morphology of the system and its resemblance to certain components of the vascular system of higher forms. The lymph system in trematodes is the natural starting-point in any study of the phylogenetic development of vascular systems.
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  • 83
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    Journal of Morphology 50 (1930), S. 193-208 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The retina of Phrynosoma cornutum bears fovea, pecten, and many varieties of cones. The light band visible in fresh retinae beneath the slit of the eyelid corresponds to a zone of action current responses characterized by a low ‘B’ rise (negative response of Chaffee.) The lack of response from pecten and fovea is due to leakage and failure to tap ganglionic fibers.Relief maps for ‘on’ and ‘off’ effects of the ‘B’ rise were prepared.Diagrams of retinal response in cross-sections were compared with corresponding curves showing density of cone distribution. In general, the height of response is inversely proportional to the density of cone distribution.The potential change due to photochemical reaction in the average rod is on the order of 23 billionths of a volt for the ‘on’ effect and 11 billionths of a volt for the ‘off’ effect.
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  • 84
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    Notes: Number of chromosomes is 13 (♂) and 14 (♀), the same as in biparentally produced relatives. In diploid groups from partheno-produced individuals homologous chromosomes tend to lie together, as ‘doubles’ or separated but near each other. In biparentally produced individuals they have as marked a tendency to lie in oppósite halves of the plate. Chromosomes of an individual tend to persist in the same position from cell to cell in the partheno-produced, with homologues side by side arranged about one center; in the biparentally produced, with seven single members arranged about each of two centers. In the partheno-produced the cells of younger animals, or of the earlier stages of organs in older animals, have a larger proportion of ‘double’ chromosomes or closely associated homologues.These conditions suggest that the partheno-produced individual arises from an egg with a single pronucleus in which there were seven ‘double’ or diad-like chromosomes, and the biparentally produced from an egg with two pronuclei, each with seven ‘single’ chromosomes. The paired position of homologues in Diptera may be due to synapsis-like tendencies in early cleavage, either as ‘hang-over’ effects from the preceding meioses or a different type of synapsis mechanism in Diptera. Partheno-produced male tettigids may be accounted for through non-disjunction among the four parts of the sex tetrad.
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  • 85
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    Notes: Experimental studies on the responses to light in Mya arenaria L. indicate that photosensitive tissue is located somewhere near the inner surface of the siphon and that the siphon is sensitive throughout its entire length.A histological study of the siphon shows cells of a special type in the photosensitive region, which are most abundant where the inner surface of the siphon is most sensitive. They are found throughout the length of the siphon, just beneath the inner epithelial layer, around both the incurrent and excurrent siphons. They receive nerve elements from branches of sixteen large nerves.Each cell contains a characteristic inner structure, the optic organelle, composed of a rather large hyaline structure, the lens, which is surrounded by a network of nerve fibrillae, the retinella. Light rays, reflected from a flat mirror through the lens in these cells, are brought to a focus in the region of the retinella, irrespective of the direction of the rays.The cells are similar in structure and function to visual cells in leeches and photoreceptors in the earthworm. Available data indicate that they function as photoreceptors and that the fibrillae of the retinella are direct receptors of light stimuli.Pigment spots found in considerable number on the distal third of the siphon, and thought by some to be eyespots, are, owing to simulation of the background, probably protective in nature, rather than functional in photoreception.
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  • 86
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    Journal of Morphology 171 (1982) 
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  • 87
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    Journal of Morphology 171 (1982), S. 11-40 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cranial osteology (including the hyolaryngeal apparatus) of Rhinophrynus dorsalis (Anura: Rhinophrynidae) is described from whole skeletons and serial cross sections. Some unique features of the extensively ossified skull include the enlarged and protracted olfactory region, for which the nasals form part of the septum nasi; the relatively short maxillaries and broad premaxillaries, and the immense quadratojugal; the extreme forward position of the quadrate; the lack of a firm articulation of the pterygoid and quadrate with the neurocranium and crista parotica; the quadrate lacking the distinct processes typical of other frogs; a single foramen for Nn. II-VII; a large, distinct operculum; and a bipartite hyale.Rhinophrynus shares other unusual cranial characteristics with the other pipoid frogs, Xenopus, Pipa, Hemipipa, and Hymenochirus. Among these features are the presence of a single frontoparietal in the adult, and the absence of parasphenoid alae, palatines, and mentomeckelian bones. Rhinophrynus differs from the pipids in the lack of a columella and a palatine process on the premaxilla, and in the possession of a quadratojugal, parahyoid bone, paired prevomers, olfactory eminence, massive quadrate that lacks distinguishable processes, a modified squamosal, and a bipartite hyale.Although the cranium of Rhinophrynus is distinctive, the evolutionary significance of its unusual features will remain obscure until comparable data are gathered from other closely related groups, the Discoglossoidea and the Pelobatoidea.
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  • 88
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    Journal of Morphology 171 (1982) 
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  • 89
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    Journal of Morphology 171 (1982), S. 151-157 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An experiment was undertaken to measure directly the changing length of a jaw muscle during feeding in four intact, unanesthetized New Zealand White rabbits. Metal markers were implanted to define the anterior and posterior ends of the single belly of the digastric muscle and fluroscopic images were recorded on videotape while the animals fed on pelleted chow and carrot. Graphs of muscle length versus incisor separation were obtained by making measurements of single frames of the videotape record. The graphs revealed that when pelleted chow was being chewed the length of the diagastric muscle changed by no more than 9% of its greatest length; during the latter part of the closing stroke it changed very little. Incising and chewing carrot caused the digastric muscle to change in length continuously throughout the chewing cycle; incising carrot resulted in a 13% change in the length of the digastric muscle. The velocity of shortening is slightly less than one muscle length per second.
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  • 90
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    Journal of Morphology 172 (1982), S. 75-82 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The lateroventral muscles of Glomeris marginata keep the animal rolled up and are able to develop and maintain great tension. Their fibers are not equipped with a particularly strong contractile apparatus but can super-contract. The sarcomere shortens its resting length by up 60% and in a typical supercontraction the thick filaments pass through the Z-line into adjacent sarcomeres. The Z-line structure changes according to the contraction state: It passes from a homogeneous, dense zig-zag line in decontracted fibers to a rarified, vaguely outlined Z-band in supercontracted fibers, in which it is possible to see actin and myosin filaments. The Z-line is thus involved in an active expanding process and is functionally very different from the fragmented and discontinuous Z-line of “classical” supercontracting muscles. The different meaning of the two cases of supercontraction is discussed.
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  • 91
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    Journal of Morphology 172 (1982) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 92
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    Journal of Morphology 172 (1982), S. 159-178 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The conjugation junction of Tetrahymena has been examined by thin sections, freeze fracture preparations, and by scanning electron microscopy. The junction is formed where the anterior tips of the pairing cells attach to one another. The structure is essentially a large disk composed of two face-to-face plasma membranes separated by a gap of extracellular space measuring about 50 nm. Rows of intramembrane particles are present at the boundary between the junction and ordinary cell cortex. These particles form a ring around the junction. Subjacent to each membrane is a thick mottled layer of material. Pores form in the junction at sites of membrane fusion. Though wider than long, these structures are actually bridges of cytoplasm that connect the conjugating cells. Pores fall into certain size and shape classes, indicating that membrane fusion is highly controlled in this system. At the level of the cytoplasmic bridge the submembrane material is compact and electron-dense. Changes in the structure of the epiplasmic layer have been monitored as the normal cortex is modified during tip transformation and through formation of the mature conjugation junction. Evidence is provided that the submembrane layer plays a significant role in the regulation of pore formation. This cytoskeletal structure may also limit the extent of membrane fusion, thus controlling the size of the cytoplasmic channels.
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  • 93
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    Journal of Morphology 172 (1982), S. 209-222 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Projections from the trigeminal complex to paramedian lobule (PML) were studied in the tree shrew (Tupaia glis) by means of retrograde transport of horseradish peroxidase (HRP). Neurons which project to both dorsal and ventral folia of PML are located primarily in those areas of the trigeminal nuclear complex interpreted as nucleus interpolaris (Vi) and caudal areas of the nucleus oralis (Vo). The majority of HRP-labeled neurons lie in ventral and ventrolateral regions of Vi/Vo. No HRP-reactive cells are present in the principal (Vp), mesencephalic, or motor nuclei nor in nucleus caudalis or rostral portions of oralis. The majority of trigeminocerebellar (TC) cells are found in ipsilateral Vi; however, sparse numbers of labeled somata are present in this subnucleus on the contralateral side. Within Vi/Vo, small fusiform and medium- and large-sized multipolar neurons contain HRP-reaction product. Large multipolar cells are found primarily in ventrolateral portions of Vi/Vo, while medium and small neurons are scattered throughout the ventral half of the nucleus. Small-sized neurons are also present dorsally within Vi/Vo. Axons of labeled TC cells course laterally through the spinal trigeminal tract, enter medial aspects of the restiform body, and arch dorsally into the cerebellum.
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  • 94
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    Journal of Morphology 172 (1982), S. 271-285 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The parotid and the principal and accessory submandibular glands of the little brown bat, Myotis lucifugus (Vespertilionidae), were examined using light microscopy and staining methods for mucosubstances. The parotid gland is a compound tubuloacinar seromucous gland. Parotid gland secretory cells contain both neutral and nonsulfated acidic mucosubstances. The principal and accessory submandibular glands are compound tubuloacinar mucus-secreting glands. They contain somewhat atypical mucus-secreting demilunar cells that often appear to be interspersed between mucous tubule cells. The mucous tubule cells in both the principal and accessory submandibular glands contain sulfomucins. Demilunar cells of the principal submandibular gland contain moderate amounts of nonsulfated acidic mucosubstances, but the corresponding cells of the accessory submandibular gland contain considerable neutral mucosubstance with very little acid mucosubstance. Intercalated ducts composed of cuboidal or low columnar epithelial cells are present in all three glands. Striated ducts in all glands are composed of columnar cells whose apices bulge into the ductal lumina. Excretory ducts are composed of simple columnar epithelium, with occasional basal cells that suggest a possible pseudostratified nature. The cells of the excretory ducts also have bulging apices. All duct types contain apical cytoplasmic secretory material that is a periodic acid-Schiff positive, neutral mucosubstance. Ductal apical secretory material is more evident in intercalated and striated ducts than in excretory ducts.
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  • 95
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The larval morphology, settlement behavior, and the rapid morphogenetic movements that occur during the first 60 sec of metamorphosis of the cellularioid cheilostome bryozoan Bugula neritina have been examined and analyzed by light and electron microscopy. The larva attaches to the substratum at the onset of metamorphosis by the eversion of the internal sac. At the same time, the coronal cilia reverse their direction of beat, spreading an adhesive secreted by the neck region of the everting sac over the metamorphosing larva. During attachment, the larva goes through several configurations that coincide with the sequential contraction and relaxation of certain larval muscles. Histological and ultrastructural evidence indicates that the neck and wall regions of the internal sac are everted by the contraction of the muscles in the equatorial plane of the larva at the same time that the roof region in pulled toward the larval equator by the contraction of the axial muscles. The subsequent relaxation of the axial muscles allows the roof region to be everted by the antagonistic force generated by the sustained contraction of the equatorial musculature. After the roof region attaches to the substratum, the apical disc is temporarily retracted by a second contraction of the axial muscles. The apical disc subsequently reextends as the axial muscles relax just before coronal involution. A comparison of the ontogenetic sequence of rapid morphogenetic movements in the metamorphoses of cheilostome and ctenostome bryozoans indicates that cellularioid cheilostomes have undergone peramorphosis in the aspect of development.
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  • 96
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    Journal of Morphology 173 (1982) 
    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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  • 97
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    Journal of Morphology 173 (1982), S. 17-28 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The formation of the royal fat body was studied by electron microscopy in three species of higher termites (Macrotermes bellicosus, Macrotermes subhyalinus, and Cubitermes fungifaber). The swarming alate imago has a storage fat body typical of most insects. In non-physogastric young queens, during the fasting period, the adipocytes deplete their reserves and then, along with the increased vitellogenesis, acquire protein-synthesizing structures (R.E.R.). During the development of physogastry they progressively specialize in protein synthesis and secretion and undergo many cell divisions. The cytological change is paralleled by a spatial reorganization of the fat body. Observations on the transformation of imaginal adipocytes into royal adipocytes show that the royal fat body is derived from the imaginal fat body and not from the tracheal cells as previously claimed.
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  • 98
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    Journal of Morphology 173 (1982), S. 73-86 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the pineal gland of the wild-captured eastern chipmunk (Tamias striatus) was examined. A homogenous population of pinealocytes was the characteristic cellular element of the chipmunk pineal gland. Often, pinealocytes showed a folliclelike arrangement. Mitochondria, Golgi apparatus, granular endoplasmic reticulum, lysosomes, centrioles, dense-core vesicles, clear vesicles, glycogen particles, and microtubules were consistent components of the pinealocyte cytoplasm. The extraordinary ultrastructural feature of the chipmunk pinealocyte was the presence of extremely large numbers of “synaptic” ribbons. The number of “synaptic” ribbons in this species exceeded by a factor of five to 30 times that found in any species previously reported. In addition to pinealocytes, the pineal parenchyma contained glial cells (oligodendrocytes and fibrous astrocytes). Capillaries of the pineal gland of the chipmunk consisted of a fenestrated endothelium. Adrenergic nerve terminals were relatively sparse.
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  • 99
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    Journal of Morphology 171 (1982), S. 293-303 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Each maxilla of fourth instar Toxorhynchites brevipalpis bears nine sensilla: Four are located at the tip of the maxillary palp and five on the maxillary body. At the palp tip are three tapered pegs on bulbous bases (MS1, MS2, MS6) that are innervated by four, two, and two neurons, respectively, and probably function in chemoreception. Also at the palp tip is a sturdy, cuticular rod with a lumen (MS5) that opens distally to the exterior. The proximal end of the rod is closed by a cuticular base to which a single unbranched dendrite containing only a few microtubules is attached. The function of MS5 is enigmatic; possibilities include mechanoreception and detection of infrared radiation.On the maxillary body are two tapered pegs on a common bulbous base (GS1, GS2) that are each innervated by three neurons, and probably are chemosensory. Three setae also occur on the maxillary body. They arise from prominent sockets and are each innervated by a neuron terminating at the hair base as a tubular body, a characteristic of cuticular mechanosensilla.The maxillary sensilla are innervated by a total of 18 neurons: 14 are probably chemosensory, three mechanosensory, and one is of unknown function. These results, combined with those from a previous study on antennal sensilla (Jez and McIver, '80), indicate that the mechanosensitive neurons of the antennae and maxillae are a relatively small percentage of the total mechanosensilla on the entire larva. In contrast the chemosensitive neurons of the antennae and maxillae provide most of the information about the chemical environment of the larva.T. brevipalpis has three less than the maximum of seven maxillary palpal sensilla found in larval mosquitoes so far studied. This difference may reflect a lesser need for sensory information about the acceptability of potential food in predators compared to browsers and filter-feeders.
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  • 100
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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