bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the lymph system of digenetic trematodes
Authors: Willey Charles H. 
Published: February 2005

AbstractA 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.
Metamorphosis in the honeybee
Authors: Oertel E. 
Published: February 2005

AbstractHistological 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.
The effects of breed on the growth of the chick embryo
Authors: Byerly Theodore C. 
Published: February 2005

AbstractThe 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.
A study of chromatin diminution in Ascaris and Ephestia
Authors: Fogg Lloyd C. 
Published: February 2005

AbstractThe 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.
The formation of the sex glands and germ cells of mammals. V. Germ cells in the ovaries of adult, pregnant, and senile albino rats
Authors: Hargitt Geo. T. 
Published: February 2005

AbstractOvaries 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.
Effect of composition of air on the growth and mortality of the chick embryo
Authors: Romanoff Alexis L. 
Published: February 2005

AbstractThe 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.
The embryogeny of the Polyctenid, Hesperoctenes fumarius Westwood, with reference to viviparity in insects
Authors: Hagan Harold R. 
Published: February 2005

AbstractFour functional types of viviparity are recognized, and the last, pseudoplacento viviparity, is illustrated by a review of the embryogeny of a species of Polyctenidae. This insect normally has ten embryos in the reproductive tract in successive stages of development. The problem of fertilization is discussed, for there seems to be no spermatheca and spermatic clumps are present in the haemocoel. No organ of Berlese can be found. One, apparently a nymph, when sectioned revealed spermatozoa in even greater abundance than the mature females. Four to six of her offspring would seem to be paedogenetic.Females liberate ova that are yolk‐free, and no chorion is secreted about them. Blastomeres are distinct, the embryonic envelopes are formed as usual, and hemipteran embryology occurs. The trophserosa functions until blastokinesis takes place, when the pleuropodial extensions evaginate and encompass the embryo which now lies in a pleuropodial cavity. The pleuropodia function as Lutrient organs, or psedoplacenta, until shortly before birth. At birth the embryo is a little more than one‐third the adult body length and bears strongly developed setae.
Life cycle, sex differentiation, and testis development in Melanoplus differentialis (Acrididae, Orthoptera)
Authors: Nelsen Olin E. 
Published: February 2005

AbstractThe general morphological and histological evidence accumulated by this study suggests the following facts:

Under out‐of‐door conditions, in the vicinity of Philadelphia, Pennsylvania, embryonic development begins at deposition and continues to the middle or late spring, when hatching occurs. The postembryonic development is completed during the summer. Copulation and oviposition occur in the late summer and early fall.
The embryonic development may be divided as follows:

The prerevolution period, in which the rudiments of organs and systems are formed.
The early‐revolution period, during which the direction of the embryo in the egg is reversed.
The late‐revolation period, or time of yolk circumcrescence and completion of the dorsal wall of the embryo.
The postrevolution period. comprising development from yolk engulfment to hatching.

The sexes are differentiated during the early‐ and late‐revolution periods.
In the differentiation of the genital rudiments, a) the germ cells are segregated into groups; b) and indifferent mesodermal element grows in among the germ cells of such a group; c) the processes of this cell (the apical cell) form intimate connections with the processes of connective‐tissue elements surrounding the germ‐cell group; and, d) the covering membrane of the genital rudiment grows in between the various germ‐connective‐tissue cell groups, completing the rudiment of the follicle.
When the adult condition is reached the testis is functionally differentiated.
The development of the carp, cyprinus carpio. I. The larval life of the carp, with special reference to the development of the intestinal canal
Authors: Smallwood W. M. , Smallwood Mary Lovett 
Published: February 2005

AbstractThe detailed spawning habits and hatching period are described. The larval period is divided into the inactive, when the yolk is the source of food, and the active period, when food is captured. The rate of growth and transformation of the larvae into fry is described.The cell formation passes into a syncytial period, when there are produced many nuclei without cytoplasm.c division. Around these nuclei, the cytoplasm collects to give rise to more cells. The method by which mucous cells are produced is described and also the presence of secretion masses in both the mucous cells and the syncytium of the mucosa.
The development and the regeneration of the color pattern in brachydanio rerio
Authors: Goodrich H. B. , Nichols Rowena 
Published: February 2005

AbstractThe teleost fish Brachydanio rerio is strikingly marked with longitudinal black stripes, which extend into the caudal fin and across the anal fin. Removal of the anal fin is followed by complete regeneration of the fin and of its normal color pattern. Microphotographic studies show that melanophores are at first uniformly distributed in the regenerating tissue and that later the melanophores disintegrate in the zone of the future light stripe and increase in the region of the future dark stripe. Observations on the normal development of the fin where the history of the individual melanophores has been followed show the same mode of formation of the stripes.
Modified mitosis in the chick embryo
Authors: Stough Howard Brown 
Published: February 2005

AbstractA study of cell division in the chick embryo has revealed in striated muscle and in the early stages of all the principal tissues and organs a process, followed by the greater percentage of the dividing nuclei, which resembles amitosis, but is undoubtedly a highly modified form of mitosis. This process is designated ‘modified mitosis’. The belief that this is essentially mitotic rests upon the fact that a number of discrete bodies may be distinguished in the one or two chromatin masses of each nucleus. These masses, or ‘mulberries’, might easily be mistaken for nucleoli or karyosomes were it not that they exhibit division by elongation and constriction. These structures probably represent masses of minute and closely clumped chromosomes in somatic number dividing in a qualitative and a quantitative fashion. As additional evidence there are present between the dividing mulberries exceedingly fine fibers which possibly represent an attempt at spindle fibers. Neither centrosomes nor asters are present, but since, if present, they would have to be of the intranuclear variety (the nuclear membrane never disintegrating) their absence is immaterial. The nucleus divides not by constriction, but by the formation of a nuclear plate. This process of modified mitosis is probably a device which favors the speed of nuclear proliferation necessary to such rapidly growing tissues.
Insect development. IV. External morphology of grasshopper embryos of known age and with a known temperature history
Authors: Slifer Eleanor H. 
Published: February 2005

AbstractEggs of Melanoplus differentialis, a grasshopper, secured immediately after they had been laid, were placed in a water bath kept at 25°C, and allowed to develop for definite periods. After fixation, the embryos were dissected out of the eggs and drawn. Large numbers of eggs were examined in order to determine the degree of variation under specific conditions. For the stages following revolution, eggs were used in which ‘hibernation’ had been prevented by exposure to low temperatures.
The spermatogenesis of the mouse (mus musculus, var. albula)
Authors: Cutright Paul R. 
Published: February 2005

AbstractThe previously reported diploid number of forty chromosomes has been verified; the sex chromosomes have been shown to exist early in the growth period and to be of the X‐Y type; and a chromosome‐nucleolus has been described in the resting stage of the primary spermatocytes which persists throughout synapsis and divides at the time of diakinesis into two parts that are equal in size and are thought to be the largest pair of autosomes. The diakinetic bivalents have been described rather fully. These are short and heavy and assume a great variety of shapes, the most characteristic of which are ring, V, Y, cross, and hexagonal. The union of bivalents during diakinesis has been shown to be an intimate one; in every instance first chromomere unites with first chromomere or third chromomere with third chromomere. This is considered to be significant evidence of the allelomorphism of chromomeres in mammals.
A study of the Golgi elements
Authors: Nahm Laura J. 
Published: February 2005

AbstractThis investigation was undertaken to determine some of the variables involved in the demonstration of the Golgi elements. Gland cells of vertebrates were studied vitally, after impregnation by osmic acid methods, and after autolysis.The duration of the staining period and the concentration of the stain condition the results obtained by vital staining with neutral red. The success of impregnation of Golgi elements with osmic acid varies with,(1) the type of tissue, (2) the time of initial fixation in relation to the time of the death of the animal, (3) the position of the cell in the piece of tissue, and, (4) the temperature of incubation with osmic acid. Stages in the impregnation of Golgi elements can be followed by examining preparations of the same tissue at frequent intervals during the incubation period. An increase in the amount of material which reduces osmic acid and which may form Golgi elements occurs in the cells during autolysis.The results are interpreted as indicating that Golgi elements are visible products of chemical reactions that occur in cells. They represent localized regions containing particular classes of chemical compounds which may be present, as such, in living cells or result from transformations in the cells during incubation. It is suggested that for the cells under consideration these substances may be unsaturated fatty acids.
The inheritance of cataract in man, pedigree and interpretation
Authors: Hornback Edward T. , Garis Charles F. 
Published: February 2005

AbstractFrom a mating of first‐cousins, of whom the female had cataract, there issued in four generations a progeny of 138 individuals, 33 of whom had cataract (23.8 per cent). Discounting the last generation, about which little is known, also discounting other unknown members, there were 29 known unaffected, 30 known affected, i.e., 50.8 per cent had cataract. The pedigree by generations shows that cataract is inherited as an autosomal (Mendelian) dominant. However, the mode of inheritance is atypical in that the defective gene for cataract may be borne, and is so borne because transmitted, without producing in the bearer its characteristic defect. In the second generation there were four of a family of nine with cataract; of the five without cataract two produced cataractous offspring and three did not marry. The literature is replete with pedigrees in which cataract is inherited as a typical autosomal dominant; there are a few pedigrees (four are reproduced) in which the mode of inheritance, while distinctly that of an autosomal dominant, resembles the present pedigree in being atypical. It is concluded that cataract is inherited as an autosomal dominant, but that in some cases it is produced only under certain conditions. These conditions are as yet not definitely known. Clinical writers seem to favor the view that nutritional and endocrine disturbances predispose to the realization of the defect.
The rudimentary copulatory organ of the domestic fowl
Authors: MacDonald Elizabeth , Taylor Lewis W. 
Published: February 2005

AbstractThe rudimentary copulatory organ of chickens was first observed as a phallic knob in 6‐day embryos. This phallic knob enlarged similarly in both male and female embryos up to the twelfth day: from the twelfth to the seventeenth day it was distinguished by a large process in the males and a diminishing process in the females. Further differentiation took place from the eighteenth to the twenty‐first days: some females lacked the porcess, others retained a smaller process than that of the male. As growth advance, fewer females retained the process until at 12 weeks of age it had entirely disappeared. The process was found in all males and showed no retrogression, whereas the few capons examined lacked it. A ridge‐shaped ‘pseudo’ process developed at about 1 week in some females and was present up to 3 weeks of age. Histologically and embryologically, the process was seen to possess some characteristics of a penis. The cloacal method of sex determination might be used with an average maximum accuracy of about 90 per cent in living day‐old chicks.
The anatomy and blood supply of the urogenital system of lepidosteus platystomus rafinesque
Authors: Pfeiffer Carroll Athey 
Published: February 2005

AbstractA description of the urogenital system in both sexes of Lepidosteus platystomus Rafinesque, and new observations on the blood supply to this system as well as to the rest of the viscera is given.The testes resemble the true piscine type. The sperm are carried by numerous vasa efferentia to the kidney tubules, through the mesonephros to the wolffian duct, and to the exterior as in the elasmobranchs and amphibians. The most anterior of the vasa efferentia are non‐functional. The ovaries are simple sac‐like structures continuous with their ducts. The oviducts transverse the ventro‐lateral surface of the mesonephros, and enter into the dilated portions of the wolffian ducts, where they join, directly anterior to the urogenital aperture. There are no ducts in the male homologous with the oviducts of the female. The kidneys fused posteriorly, appear to extend the entire length of the body cavity, but the anterior third is non‐urinary.By injection methods, the celiaco‐mesenteric artery is shown to be crowded to the posterior end of the body cavity by the complicated swim‐bladder, and runs anteriorly to supply the entire viscera. Its anterior portion is incorporated in the liver.
Spermatogenesis in gecko japonicus (dumeril and bibron)
Authors: Wu Su‐Hsuen 
Published: February 2005

AbstractThe nuclear changes involved in the two maturation divisions of G. japonicus have been studied in considerable detail. All observations compel a telosynaptic interpretation. The duality, an apparent parasynapsis, as seen beginning from synizesis up to diplotene is a result of a longitudinal splitting of the chromosomes joined end to end. Strepsinema is brought about by breaking up of the diplotene thread into segments, which really are pairs of synaptic mates in end‐to‐end union; each segment then bends at its middle to form V‐ or ring‐tetrads. There are altogether twenty tetrads. All chromosomes assume a rod shape when in the metaphase plate. A pair of heterochromosomes was observed to be slower than the rest in assuming the rod shape and in getting into the plate. The marching of the synaptic mates toward their respective poles is asynchronous. Second division begins right after the chromosomes have reached the poles. Zwischenkörper observed at the end of the second division are regarded as formed by the granules seen in the polar regions during the first division.
Studies of the epithelium lining the caeca and mid‐gut in the grasshopper
Authors: Woodruff B. H. 
Published: February 2005

AbstractThe alignment and condition of mitochondria in the epithelial cells indicate that secretion is apparently the chief function of the midgut and the attached caeca. In view of the response of these cells to vital dyes, and to various fixatives, other cell structures–particularly vacuoles–are uncertain evidence of cell activities. Many structures visible by means of vital dyes indicate changes in the permeability of the cell membrane, and subsequently in the cytoplasm. Hence, they are artifacts, just as truly as those found in fixed tissue.
The relationships of the medullae and cuticular scales of the hair shafts of the soricidae
Authors: Smith Helen Hoffman 
Published: February 2005

AbstractMid‐dorsal protective hair‐shafts from forty‐five species of Soricidae were studied with the object of investigating the relation between the differences in certain microscopic structural elements and the diameters of the shafts in which they were developed, and the possible occurrence of specific characters in these elements. In comparing like portions of like hair‐shafts, it was found that scale‐ and medulla‐forms were related (with slight variations within their form‐groups) to the diameters of the hair‐shafts in which they were developed. It is possible that further study of these slight variations may show them to be associated with the species bearing the hair.