bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the thyroid gland in the chick embryo
Authors: Hopkins Marie Lockett 
Published: February 2005

Abstract1. The developing chick thyroid consists of epithelial plates or cords suspended in a sinus, probably lymphoid. These cords in cross section have the appearance of follicles.2. Growth in size is accomplished by fusion of follicles. Growth in number of the latter by proliferation of inter‐follicular epithelial cells.3. Colloid first appears on the tenth day of incubation. The tadpole test indicates the beginning of functional activity at this time.4. During development there is a progressive decrease in the cytoplasm‐nucleus ratio from 3.3: 1 on the third to 1.5: 1 on the nineteenth day, as measured in area, not volume.5. Not only is chromophobe and chromophile colloid present in different cells of the same follicle at the same time, but both are occasionally present in the same cell at the same time.6. Evidence of heightened activity in the chick thyroid are as Uhlenhuth (′28) describes them in salamanders: namely, high columnar cells, apically located secretion granules, and vacuoles of chromophobe colloid.7. Follicles in late developmental stages have, at some time during their functional cycles, tubular exits, which are thought to represent one path through which colloid reaches the circulatory spaces.8. Vital staining indicates that elements of the reticulo‐endothelial system are present in the developing thyroid. Phagocytic cells in the gland of one embryo were observed phagocytosing entire erythrocytes.
Studies on cell number and the progression factor in the growth of Japanese beetle larvae (Popillia japonica Newman)
Authors: Abercrombie W. Fulton 
Published: February 2005

AbstractIncreases in weight, total body length, and width and length of the head capsule of Japanese beetle larvae were studied. Since the progression factors decreased with succeeding molts and exhibited considerable variation it was concluded that Przibram's principle is inapplicable. Cells were counted in the mid‐intestine and brain. Columnar cells of the mid‐intestine were measured. The data show: (a) No increase in cell number occurs at the time of molting. (b) The progression in weight and length cannot be correlated with an increase in cell number. In the first instar the progression for increase in weight was 5.73; while for increase in cell number, it was 1.67 for the mid‐intestine, and 1.19 for the brain. In the second instar, the corresponding figures were 5.24, 1.98 and 1.69. In the third instar average weight increased 3.18 times, but there was practically no increase in cell number. Thus, molting does not represent a definite increase in number of cells of the insect's body as suggested by Przibram and Megusar, and Bodenheimer's method of calculating cell divisions seems to have no factual basis. Increase in size of the larva is largely due to an increase in cell size. The ratio of increase in total cell volume of the columnar cells of the mid‐intestine is approximately equal to the ratio of weight increase.
Branchial glands in fishes
Authors: Bevelander Gerrit 
Published: February 2005

AbstractIn a comparative study of the branchial epithelium of fishes we find the occurrence of three distinct types and seven subtypes of intra‐epithelial glands which are in intimate association with the branchial epithelium of fishes.These glands have been classified according to their morphological patterns, cytoplasmic content and other features dealing with structural complexity.Although these structures arrange themselves in a graded series which become increasingly more and more complex, there does not appear to be any definite correlation between the structural complexity of the glands, and the apparent evolutionary history of the fishes.We conclude from the characteristic arrangement, relationships, and specific staining reactions that these structures are intra‐epithelial mucous glands.
Oögenesis, fertilization and early cleavage in Habrobracon
Authors: Speicher B. R. 
Published: February 2005

AbstractSince differential maturation has been used in explaining sex determination in Hymenoptera, the pertinent stages were studied cytologically in Habrobracon by using whole mounts of timed eggs stained by the Feulgen reaction.The egg is laid with the maturation figure in an arrested first anaphase close to the ventral egg surface, and with the spindle horizontal to the latter. Eggs from different stocks show differences in position of maturation figure. A single sperm enters during oviposition, the maturation spindle revolves to a vertical position and normal maturation and change of the sperm ensues. Nuclei of unfertilized eggs behave similarly. Ten chromosomes enter each of the three polar and the one matured egg nuclei, the latter being always the innermost of the four. Unfertilized eggs have ten chromosomes at first and eleventh cleavages; fertilized eggs have around the expected twenty. Chromosomes in maturation divisions are too small and round to show individual differences. There is no good evidence of chromosome elimination.
The anatomy and histology of the alimentary tract of the grasshopper, melanoplus differentialis Thomas
Authors: Hodge Charles 
Published: February 2005

AbstractThis investigation is intended to be the first of a contemplated series to study correlation of diet with morphological change. The material here reported is from grasshoppers on satisfactory diets. The gross anatomy shows a typically acridine arrangement. Fixation with B3 and staining with haematoxylin and eosin shows that peritoneum, muscle and chitin in different areas vary only in arrangement and relative development. The epithelial cells of the various regions differ in structure as well. Modifications of the cytoplasmic elements of these cells are correlated with cellular activity. The epithelial cells of the mid‐gut and its six bi‐lobed gastric caeca, and of the six rectal glands have a striated border of separate filaments which are cilia‐like in appearance but devoid of motion. The caeca are most active in gastric secretion, which is merocrine or holocrine according to conditions. Essentially different granules and vacuoles are secreted, and extruded by rupture of the cells; which are replaced from nidi.
Haploidy and aberrant spermatogenesis in a coleopteran, Micromalthus debilis LeConte
Authors: Scott Allan Charles 
Published: February 2005

AbstractThe coleopteran Micromalthus debilis LeConte has two additional female reproductive forms besides the male and female adults. One of these is a paedogenetic viviparous female which produces female offspring by diploid parthenogenesis; the other is a paedogenetic ovoviviparous female which produces males by haploid parthenogenesis; The male has been shown to be somatically haploid in both early and late stages of development, while all three female types are diploid. The first spermatocyte division is completely abortive as regards division of chromosomes and cell. However, a very characteristic unipolar spindle is regularly formed. The chromosomes of the first spermatocyte anaphase move away from the single pole with their attachment regions hindermost. The spindle consists of ten fibers, each one connecting a chromosome with a single pole. They elongate during the anaphase. The second spermatocyte division is apparently normal in all respects and it ultimately results in two normal sperm. It has been shown that the theories of Belar, Bleier and Schaede concerning the problem of chromosome movement are deficient in view of the peculiarities of this monocentric mitosis.
Embryology of the nervous system in the grasshopper, Melanoplus differentialis (Acrididae; Orthoptera)
Authors: Baden Victor 
Published: February 2005

AbstractThe development of the nervous system is traced by stages and, in general, is found similar to that already described for other insects. Terms such as ganglionic gangliomeres, medullary masses, optic nerve, etc., are shown to have no significance. The intraganglionic thickening of Viallanes is shown to be a misnomer. A chronological table of the developmental processes is appended.
Spermatophores of the snail Neritina reclivata
Authors: Andrews E. A. 
Published: February 2005

AbstractDiffering from hitherto known spermatophores, these are found to have the form of a loop with a thick body and the slender ends twisted together.Also one end bears a spiral row of triradiate spicules, unique in being chitinoid secretions. Each is formed within a vacuole of a cell of a small gland found in the males. The ends of the spermatophores hold sperms, but the main mass consists of granules of problematical value. Spermatophores after discharge are stored up within the female, where remnants of them remain indefinitely.For the first time stages in the formation of spermatophores were found within the males. The head organ in the male is found to be more complex than hitherto known in this genus. A special head organ in the female is described for the first time in this family. An hypothesis is advanced as to the possible use of these male and female head organs in transfer of spermatophores. The suggestion is made that in this family the spermatophores and their organs of transfer and of storage may serve as generic characters.
Cell division and differentiation in the growth of specialized vertebrate tissues
Authors: Cohen Arthur , Berrill N. J. 
Published: February 2005

AbstractThe post‐embryonic growth of the notochord, sensory retinal cells, cartilage and gut epithelium in frog tadpoles, trout and lamprey is described. Increase in the number of notochord and sensory retinal cells results only from the mitotic division of cells which have not yet undergone the structural modifications characteristic for these cells. The specialized and functional cell does not divide. In the frog tadpole the cartilage cells increase by mitotic division of the fully‐formed and functional cell: in addition there are centers of proliferation consisting of small, rapidly‐dividing cells. The trout is similar except that there are no centers of proliferation, in addition amitotic division occurs. The gut epithelium grows by mitotic division of the functional constituent cells. During division the cell assumes a spherical shape and its functional activities are suspended.
Studies in teleostean reproduction. I. Embryonic hermaphroditism in Lebistes reticulatus
Authors: Dildine Glenn C. 
Published: February 2005

AbstractA study has been made of 155 Lebistes embryos, extending from fertilization until birth of the young. A period of embryonic hermaphroditism begins soon after the formation of the genital ridges (3.0 mm.) and continues until birth (6.5 to 7.0 mm.). Development is first ovarian; evidence is the universal occurrence, in all gonads, of many germ cells in typical ovarian synapsis. The gonads of one‐half of the embryos soon become testicular while those of the other half continue to develop as ovaries. In testicular gonads, all synaptic germ cells undergo pycnotic dissolution as the gonad hilus organizes into a prospective medulla. In ovaries, germ cells in synapsis continue to enlarge as definitive ovocytes. This embryonic hermaphroditism supports Witschi's explanation of sex determination in Lebistes, based on his own work on frogs and on Winge's discovery of unusual XX males in Lebistes. The embryology of gonads in Lebistes also suggests that in teleosts, as in amphibians, birds, and mammals, gonads develop from two distinct portions, a male medulla and a female cortex.
Observations on sperm formation in the centrurid scorpions with especial reference to the Golgi material
Authors: Wilson Edmund B. , Pollister Arthur W. 
Published: February 2005

AbstractThe Mexican scorpion Centruroides shows exactly the same type of chondriokinesis (by ring formation) as that hitherto known only in the related form Centrurus, as earlier reported by one of us ('31). The Golgi bodies show no trace of ring formation but are distributed by random assortment like that of the chondriosomes in other scorpions. The Golgi bodies, clearly visible in vivo, show the typical plate‐like or lamellar structure characteristic of them in other forms. In the first division, after Weigl, there appear to be two metaphase stages, an earlier one in which the dictyosomes are irregularly scattered and a later one in which they tend to mass near the mitotic poles. In the same division, after Champy‐Kull, the (presumable) dictyosomes are regularly massed near the poles and may be traced through the whole mitosis. The neural red bodies (‘vacuome’) undergo an irregular distribution and are cast out in the slough. The problem of distribution and localization in the sperm‐cell formation are discussed with reference to the principle of genetic continuity in the germ cell.
The development of the cortical adrenal in the four‐toed salamander Hemidactylium scutatum (Schlegel)
Authors: Branin Manlif Lelyn 
Published: February 2005

AbstractAccounts of cortical adrenal development in urodeles are few in number and mostly incomplete from the point of view of development. Hence, an investigation was initiated to fill in existing gaps and present a complete developmental history of the glands in one of the urodeles.The primary anlagen of the cortical adrenal (interrenal) were seen first in the 8.8‐mm. embryo as paired or unpaired cell groups in the interrenal area of the 'tween zone lying either in contact with or just beneath the coelomic epithelium. It was not possible to determine definitely whether they originate from the coelomic mesothelium or from the subjacent mesenchyme. Subsequent primordia are formed continuously throughout the period of larval development in an antero‐posterior time sequence. Almost immediately they become associated with the postcaval system and the relationship thus established persists throughout life. There is no evidence of a budding process as described by Albrand ('08).During development there is a progressive increase in the size and number of cortical masses, an increase in the total area occupied by them, and a posterior shifting of the tissue as a whole as determined by its position in relation to the spinal ganglia. The definitive distribution is attained at the time of metamorphosis. The tissue occurs abundantly along the postcava, but strands along the median edge of the mesonephroi, as in some urodeles, are only sparingly developed.
Reproductive system of the bruchid beetles bruchus quadrimaculatus Fabr., bruchus (callosobruchus) chinensis L., (bruchidae—Coleoptera)
Authors: Mukerji Durgadas , Bhuya M. A. Hakim 
Published: February 2005

AbstractThe reproductive organs of Bruchus quadrimaculatus Fabr., and B. (Callosobruchus) chinensis L., including histology are described in detail. The role of the different parts of the male and female copulatory apparatus is discussed and the physical composition and function of the secretions of the accessory glands are indicated. The specific differences in the structure of the genitalia of the two species are shown.
An analysis of the early development of the chick by means of the mitotic index
Authors: Derrick G. Ethel 
Published: February 2005

AbstractUsing the percentage of mitotic figures in the cells as an index, a study was made of the distribution of cell multiplication in the development of the chick embryo. Counts were made of all regions in embryos ranging from the embryonic shield stage to sixteen somites, and of the neural and sensory epithelia and axial mesoderm of older embryos. Figures are presented which are believed to establish the sufficiency of mitotic division in producing the cell increases in the early embryo. In the developing primitive streak, areas of superior division rate were found in the presumptive medullary plate ectoderm at the sides of the streak. The node and the primitive plate tend to exhibit lower rates than the axis of the streak. The posterior nerve cells multiply more rapidly than the average of the neural tube, and areas of activity in the mesoderm tend to be located near the posterior end. An antero‐posterior gradient of the index is indicated in the anterior neural tube, meeting a transient postero‐anterior gradient of the hinder cord in the yolk‐sac region. A lower rate of division in the floor than in the sides of the neural ectoderm may be implicated in the inrolling of the medullary plate and in the ventral ourvature of older embryos. All indices drop progressively with advancing age and differentiation.
The growth, maturation and atresia of ovarian eggs in the rabbit
Authors: Pincus G. , Enzmann E. V. 
Published: February 2005

AbstractA study is made of the development of ovarian ova in mature rabbit does before and during various stages of pregnancy and after the injection of thyroid and anterior‐pituitary‐like hormones. No appreciable ovogenesis during sexual maturity was found. Nine types of ovarian follicle are distinguished according to size and degree of development. Full ovum size is reached in pre‐antral follicles, and is marked by the formation of a dictyate nucleus and slight reduction in nuclear size. Full follicle size is attained much later. The nature of follicle migration in the course of development is described. Ovum migration within the follicle is found to be a consequence of the nature of the egg's attachments to the follicular epithelium. The least atresia is found in young oocytes (10%), the larger follicles showing about 60% atretic at all stages of the reproductive cycle. The hormone preparations administered affect only the largest follicles and their contained ova.
Changes in the volume, form and internal architecture of the nuclei of the granular glands of the integument of the newt, Triturus viridescens
Authors: Dawson Alden B. 
Published: February 2005

AbstractConcomitant with the appearance of the early secretion granules the nucleus enlarges slightly, the basichromatin is reduced and discrete acidophilic granules appear within the nuclei. Some nuclei become vacuolated and in others the basichromatin is practically reduced to a thin shell reinforced with occasional chromatic strands. Such nuclei are filled with acidophilic granules.In many instances the portion of the nucleus adjacent to the secretion is greatly modified, the basichromatin is reduced and presents an alveolar pattern with the alveoli filled with acidophilic material and elongated at right angles to the nuclear membrane. This appearance suggests that material is passing from the nucleus into the cytoplasm but no cytological evidence of such a passage was obtained.During the storage phase giant nuclei are present. They appear to be the result of a simple hypertrophy but in a few instances it appeared that multiplication by direct division, followed by coalescence might be a contributory factor to their formation.Following thyroidectomy or hypophysectomy the production of secretion was retarded but no profound regression was observed. After treatment with implants or injections of anterior pituitary a mild stimulation was observed.The evidence for nuclear participation in the formation of secretion is not conclusive but many of the changes which occur strongly suggest such an activity.
The trophotaeniae of the goodeidae, a family of viviparous cyprinodont fishes
Authors: Turner C. L. 
Published: February 2005

AbstractThe embryos of twenty‐one species of the family Goodeidae have extensive rectal processes (trophotaeniae) which serve as absorptive organs, by means of which the embryos while they are retained in the ovarian cavity absorb substances dissolved in the ovarian fluid. Embryos of three species have not been available for study. No trophotaeniae are present in one species Ataeniobius toweri. There are three general types of trophotaeniae, rosette, sheathed and unsheathed. The structure of the trophotaeniae is sufficiently constant in each species to be used in species determination.
The occipital, otic, basicranial and pterygoid regions of the Gorgonopsia
Authors: Olson Everett Claire 
Published: February 2005

AbstractThis paper is based on information derived from a sectioned skull of Cynariops robustus Broom, a prepared skull of Cynariops longiceps Olson, prepared and sectioned specimens of Captorhinus, Dimetrodon and various cynodonts, and the literature dealing with these forms.In the otic region, it is shown that the internal auditory meatus, the fallopian aqueduct and the semicircular canals change but little in the series from Captorhinus to the cynodonts. Certain structures, the fenestra ovalis, which becomes progressively smaller, the vestibule, which lies progressively more ventral to the floor of the brain case, the recessus lagenacochlea, which increases in size, and the prootic, which enlarges, show progressive change. The fenestra rotundum is discussed at length. It is absent in Captorhinus, just back of the fenestra ovalis in the Gorgonopsia and Dimetrodon, and confluent with the foramen jugularis in the Cynodontia.The length and relationships of the parasphenoid in the Gorgonopsia are offered as evidence supporting the theory of the homology of the reptilian parasphenoid and the mammalian vomer.The sphenethmoid complex in Cynariops is divided into two elements, a basal member, the presphenoid, and a dorsal member, identified as the orbitosphenoid but possibly incorporating a portion of ossified mesethmoid as well.The comparative studies point out certain basic trends of evolution in the Synapsida, and indicate the level of evolutionary development of the groups studied.
The morphology of the aortic arches in four genera of plethodontid salamanders
Authors: McMullen Eleanor C. 
Published: February 2005

AbstractThe larval, metamorphosing and definitive aortic arches of Desmognathus fuscus, Plethodon cinereus, Eurycea bislineata, and Gyrinophilus porphyriticus, described in this paper, were investigated because it was thought possible that, if the fourth or pulmonary arch failed to develop in these lungless forms, a new factor associated with the loss of lungs might be revealed.The salient points of structure disclosed, so far as the problem involved is concerned, are: D. fuscus and P. cinereus develop fourth arches which remain functional in the larvae and adults and supply the pharynx, oesophagus, stomach and skin of the shoulder region. In some instances the fourth arch in the larvae of P. cinereus is reduced in length or entirely lacking in which cases correspondingly less of the fourth arch and more of the third arch is present in the adult. E. bislineata and undoubtedly G. porphyriticus fail to develop fourth arches and hence do not possess these in either the larval or adult states.It is concluded, therefore, that the failure of the fourth arch to develop has evidently not been a factor involved in the advent of lunglessness in plethodontid salamanders. Also, the fact that E. bislineata never develops a fourth arch, yet is able to transform, furnishes additional evidence against Figge's view that Necturus fails to metamorphose because the ventral portion of the fourth arch is absent.
Origin and fate of the median cord in the grasshopper, Melanoplus differentialis (Acrididae: Orthoptera)
Authors: Baden Victor 
Published: February 2005

AbstractThe median cord arises as a hypodermal invagination along the midline from stomodeum to end of tenth abdominal ganglion. It separates from the hypoderm, but does not differentiate into any tissue; apparently it degenerates.