bluuebunny/crossref_metadata_2025_split huggingface dataset:
A detailed study of the endoderm of hydra
Authors: McConnell Carl H. 
Published: February 2005

AbstractThe flagella of the endodermal cells of hydra have their origin in the form of a cytoplasmic spherule which appears on the cell membrane just above the blepharoplast. This spherule moves outward, and in doing so forms a small cylinder, which, in time, flattens down into a ribbon‐like flagellum, the edge of which is slightly thickened. Endodermal cells were found to bear from one to five of these flagella. Dissociated endodermal cells become amoeboid and are able to move about quite freely, taking up particles of food with pseudopods; these cells are also able to elaborate flagella. In the normal well‐fed hydra the endodermal cells are found to fragment endogenously; these endogenous fragments pass to the tentacles and other outlying regions, where they are taken up by the endo‐epithelio cells lining these regions. The endoderm is frequently thrown into villi of quite large size: these villi, when studied over a period of days, are found to deteriorate; the cells which composed them wander to the tentacles, buds, and basal regions by means of their flagella and amoeboid movement, where they deteriorate, the cell particles being taken up by the epithelio cells lining these areas.
A comparative study of the chromosomes of rodents
Authors: Cross James Cecil 
Published: February 2005

AbstractA comparative study has been made of fifteen species and subspecies of rodents to determine the range in number and variation in morphology of their chromosomes. The number range is between 40 and 86±, with an average number for known species of 52. In the family of Cricetidae there is little variation in chromosome number and a general similarity of the chromosomes. In the Muridae the range for known species is 40 to 42, but the chromosome morphology even of subspecies may be quite different. In Sciuridae a range of 48 to 62 has been found in different species. The greatest range in number is found in the Heteromyidae, 44 and 86± chromosomes having been found in two species. It is concluded that the stem number for rodents is close to 48 and that fragmentation and fusion account for variation in numbers, and these affect the morphology of the chromosomes. The evidence also indicates that variations in morphology are due to translocations and inversions, and possibly deletions accompanied by translocations.
The distribution of sperm‐forming materials in scorpions
Authors: Wilson Edmund B. 
Published: February 2005

AbstractThere are in scorpions two sharply contrasting types in respect to the mode of distribution of the chondriosomes to the sperm cells. In one of these the chondriosomes, spheroidal in form and nearly definite in number, are sorted out whole without division during the spermatocyte divisions, their number being thus reduced successively to one‐half and one‐fourth. This type occurs in Opisthacanthus, Hadrurus, Vejovis, Euscorpius, and Palamnaeus. In the other, as yet known only in Centrurus, all the chondriosomes fuse during the spermatocyte growth period to form a single ring‐shaped body; and this, during the two ensuing mitoses, is accurately divided into two, four, and eight equal parts, of which each spermatid receives two. In both types alike the chondrioma is thus distributed very nearly equally to the sperm cells, but by widely contrasting processes; and in both types the spermatid chondriosomes are drawn out to form the sheath of the axial filament in the sperm tail. In Opisthacanthus there are indications of a definite process of dictyokinesis during the spermatocyte divisions.These facts are discussed in the light of the general history of the chondriosomes in other animals, with especial reference to more general problems of cell division. The present vagueness and uncertainty of our knowledge of cell division and differentiation are emphasized.
Some cytoplasmic structures in the male reproductive cells of a pseudoscorpion (Chelanops corticis)
Authors: Nester Henry George 
Published: February 2005

AbstractThe chondriosomes of the germinal epithelium are vesicular, whereas the Golgi material takes three forms. The aggregation of chondriosomes about the Golgi cap, located on the nucleus, suggests a chemical interchange between these in the growth period. They become cylindrical as the Golgi cap moves from the nucleus and becomes spherical. It is at this time joined by other Golgi material. The entire aggregation is dispersed previous to the maturation divisions, where the inclusions studied are only approximately equally divided, in contrast to conditions in the true scorpion, Centrurus exilicauda. Golgi granules on chondriosomal surfaces in the spermatid again suggest chemical interchange. The later changes of chondriosome vesicles to discs, and back to spheres, may be means of regulating chemical reaction. A close relation between chondriosomes and Golgi material is indicated by various bodies, of Golgi origin, within the former in the spermatid. A thick thread finally originates from among the chondriosomes of the elongated sperm. Spiral threads surrounding the elongating nucleus arise from reunited Golgi material, a derivative of this substance not previously recorded. The acrosome, also of Golgi origin, undergoes several changes in shape and shows several parts. The elongated nucleus, spiral thread of Golgi origin, acrosome, chondriosomal thread, and unusually long axial filament become coiled and encysted in an oval mature sperm capsule. In the female duct the sperm uncoils.
A comparison between the ultraviolet microscopy and the Feulgen staining of certain cells
Authors: Wyckoff Ralph W. G. , Ebeling Albert H. , Ter Louw Adrian L. 
Published: February 2005

AbstractThis paper describes ultraviolet (λ = 2750 A) photomicrographs of resting and dividing chicken macrophages and fibroblasts and of erythrocytes and lymphocytes. The structures found in these photographs are compared with the ones brought out in fixed material by Feulgen staining and found to be essentially similar in appearance. A preliminary series of ultraviolet pictures is also shown of a single fibroblast passing through several of its stages of division.
The architecture of the parietal cells of the salivary glands of the grasshopper, with special reference to the intracellular canaliculi, Golgi bodies, and mitochondria
Authors: Beams H. W. , King Robert L. 
Published: February 2005

AbstractThe parietal cells of the salivary glands of the grasshopper are large and roughly spherical or sometimes pyramidal in form, scattered for the most part singly among the zymogenic cells of the lobules. They possess a magnificent system of intracellular canaliculi into which their secretions are directly emptied and conveyed to the exterior of the cell. These intracellular canaliculi are strikingly impregnated with osmic‐acid methods (Nassonov, Mann‐Kopsch) in a manner comparable to the contractile vacuole of Paramecium as described by Nassonov. However, in addition to the impregnated system of intracellular canaliculi, Golgi bodies are found evenly distributed throughout the cell in the form of crescents, semicircles, or ring‐like structures typical of insect tissue.Inasmuch as a direct homology between the intracellular canaliculi and the contractile vacuole of Paramecium, both from the point of view of morphology and physiology, seems justified, we question the inference drawn by Nassonov that the impregnated walls of the contractile vacuole in Paramecium actually represent Golgi material. Deduction is made from these and previous studies that the magnificent network of ‘vacuome‐Golgi apparatus’ described by Parat and Painlevé ('24) in the salivary glands of Chironomus larvae is nothing more or less than intracellular secretory canaliculi.Mitochondria in the parietal cells are abundant in the characteristic form of short rods and filaments. No evidence of a direct transformation of mitochondria into Golgi bodies. as held by Parat, was observed. Golgi bodies and mitochondria show no marked topographical relationship to the intracellular secretory canaliculi.
Coordination of ciliary movement. I. Methods of study and the relation of ciliary coordination to ciliary inhibition
Authors: Lucas Alfred M. 
Published: February 2005

AbstractA simply constructed apparatus, which includes a cinema camera, is described for the recording of ciliary movements. From data for Modiolus demissus obtained by this method, it is concluded that the coordinating impulse is a propagated impulse which regulates the temporal and spatial relationships of ciliary contractility, that this impulse has to a certain degree a determinant effect upon ciliary inhibitory influences so that the area rendered inactive is a multiple of the ciliary wave length, that the coordinating impulse is transmissible through cells bearing quiescent cilia, and that it may act as a stimulus of sufficient strength actually to cause quiescent cilia to become active.
A topographical and cytological study of the sympathetic nervous components of the suprarenal of the chick embryo
Authors: Brauer Alfred 
Published: February 2005

AbstractA study was made of the development of the suprarenal gland of the chick with reference to the following points: 1) Topographical relationship of the sympathetic cell masses to the cortical cords, and to the sympathetic nervous system. 2) Cytological differentiation of the sympathetic cells.The migrating indifferent sympathetic cells, although becoming generally distributed over the medial surface of the cortical ridge, form a series of more prominent aggregations at certain definite loci. These aggregations are the rudiments of two longitudinal ganglionic chains, which develop from the sixth to the seventh day. Around and between the ganglionic rudiments the indifferent cell groups become penetrated by sympathetic fibers from the ganglionic rudiments as well as by fibers of sympathoblasts which develop from indifferent cells of the sympathetic‐chromaffine complex. At the same time multipolar sympathetic cells lying between the cortical cords and processes to the tracts developing between the ganglia on the surface of the cortical ridge.Differentiation of ‘chromaffine cells’ from indifferent cells of the aggregations begins during the eighth day, after a profuse innervation of the rudiments has been established. Differentiation is evidenced by the appearance of cytoplasmic granules, and by the appearance of the ‘chromaffine reaction.’ The possible bearing of the innervation of the indifferent cell aggregations upon their differentiation and upon their penetration of the cortical bodies is discussed.
DIE BILDUNG DER ERYTHROCYTEN IM KERNE DER PLASMOCYTEN; DER HÄMOGLOBINSCHWUND IM BLUTKREISLAUFE MIT DER PIGMENTMETAMORPHOSE UND OHNE DERSELBEN UND DIE BESONDERE ELIMINIERUNGSART DER CHROMATINSUBSTANZ AUS DER ZELLE IM BLUTE DES BATRACHOSEPS ATTENUATUS ESCH.
Authors: Komocki Witold 
Published: February 2005

AbstractIn the blood of Batrachoseps one part of the erythrocytes is formed inside the nucleus of plasmocytes as a result of the metamorphosis of chromatin substance. When erythrocytes are completely formed, they separate themselves from the plasmocytes.Disappearance of the hemoglobin of erythrocytes with pigment metamorphosis is visible in the drawings.When the disappearance of hemoglobin with pigment metamorphosis takes place, the color of the hemoglobin cytoplasm frequently becomes very pale. The hemoglobin cytoplasm may vanish also without pigment metamorphosis in such a way that the whole cell (nucleus and cytoplasm) swells, and the cytoplasm becomes paler, and finally only a pale shadow remains which is rather difficult to distinguish. The author has noticed in the blood of Batrachoseps, besides extrusion of small nuclei from the erythrocytes, also a particular way in which chromatin substance is eliminated from the cell. While the cell and the nucleus become pear‐shaped, the nucleus moves toward the periphery, touching the surface of the cell with its funnel‐shaped narrow side. From this narrow side the chromatin substance flows out in the form of a band stained red, according to Romanowsky.
The effects of X‐rays on anterior regeneration in tubifex tubifex
Authors: Stone Raymond G. 
Published: February 2005

AbstractObservations of earlier workers concerning the limited region from which anterior regeneration will occur in Tubifex and the reduced number of segments formed were confirmed in control worms used in these experiments. Only three anterior segments are replaced when as many as twelve are removed. Regeneration is completed within 18 days.Removal of anterior segments from worms that have received 9000 (r) units exposure to x‐rays is not followed by regeneration. The wound heals rapidly and worms have been kept in laboratory 70 days without further change. Longitudinal sect ons of injured ends show that the epidermis and muscle layers extend across the wound surface to completely close the body cavity. The intestine retracts slightly and heals to form a blind tube. No mitotic figures appear in cells of this region and there is no evidence of regeneration.In control worms material for formation of the cerebral ganglia and new epidermis arises by proliferation of epidermal cells. The new pharynx arises from the region of the old intestine adjacent to the wound surface. The muscle layers of the body wall and pharynx in new segments are apparently formed by migration of cells from the old muscle elements about the margin of the wound area. No neoblasts were observed in anterior migration or in the process of formation upon adjacent septa in any of the worms.
Homology of the paired fins in fishes
Authors: Howell A. Brazier 
Published: February 2005

AbstractRecent and fossil fishes may be divided into groups having both pectoral and pelvic fins, pectorals only, pelvics only, or with a second pair of fins located anteriorly and seemingly not homologous with pelvics. In some groups the pelvics are located near the cloaca, with an extensive hiatus between the pectoral and pelvic neuromeres; other groups are of an intermediate character, while in a third group the second pair of fins appears to have no relationship to the pelvics. The character of the innervation indicates that they could hardly have been derived from the latter, and the few nerves, consecutive with the brachial plexus, which supply them suggest origin from the posterior elements of the dermal series, the anterior of which became the pectoral fins. Instances even occur (Polynemus) in which a third pair of appendages has been derived from the original pectoral complex.
The development of the external form of the guinea‐pig (cavia cobaya) between the ages of 21 days and 35 days of gestation
Authors: Harman Mary T. , Dobrovolny Marjorie Prickett 
Published: February 2005

AbstractThe authors are preparing a table for the normal developments of the guinea‐pig. This paper deals with the external form and the development of the external characteristics of guinea‐pigs between 21 days and 35 days, copulation age. About one hundred embryos were used from thirty‐six litters.Length and weight are good criteria for determining age, although there is some variation. The flexures, the disappearance of the tail, the development of hair follicles at specific locations, the degree of development of the mouth and external ear are better criteria for the determination of age.At 27 days there is a sudden increase in both weight and length. This increase is rather uniform from this period until the end of 35 days. At this time the embryo has the appearance of a newborn guinea‐pig.
The development of the carp, cyprinus carpio. II. The development of the liver‐pancreas, the Islands of langerhans, and the spleen
Authors: Smallwood W. M. , Derrickson Mary Burton 
Published: February 2005

AbstractThe first stage in the formation of the liver is two ventrolateral evaginations of the mid‐gut at the time of hatching. From the undifferentiated cells branching from the liver duct the pancreas cells arise, but do not assume adult character until the carp is about 41 mm. long.The islet makes its first appearance in the region of the pancreatic duct at the 8‐mm. stage and shows no transitional stages. In the mesenchyme itissue dorsal to the intestine the spleen arises, and is finally completely surrounded by the liver‐pancreas.
The development of the sino‐atrial region of the chick heart
Authors: Quiring D. P. 
Published: February 2005

AbstractThe development of the interatrial septum and the relation of the sinus venosus and sino‐atrial valves to the interatrial septum was followed in chick hearts ranging from 50 hours of incubation to the adult. The following singificant facts were established. The interatrial septum first appears at about 50 to 55 hours of incubation. It fuses with the endocardial cushions of the atrio‐ventricular canal, typically in the last quarter of the fifth day. Secondary perforations appear in the septum at the time of closure of the interatrial foramen primum. These are retained until hatching, although they may persist in the adult heart. The sinus venosus, a sinus septum, and the sino‐atrial valves are retained as definite structures in the adult fowl heart. The pulmonary vein and the left precava as they enter the heart form a prominent addition to the inter‐atrial septum proper which I have designated as the pars cavo‐pulmonalis. The pulmonary orifice in the left atrium is provided with an extensive flap‐like valve. A prominent limbus of Vieussens is present in the right atrium. A well‐developed median muscular arch overlies the interatrial septum and a pair of lateral muoscular arches extend over the atria. Their position would seem to be significant in the closing septal perforations during atrial systole.
The blood cells of the trematode diplodiscus temperatus
Authors: Jordan H. E. , Reynolds B. D. 
Published: February 2005

AbstractThe vascular channels and sinuses of this trematode contain three varieties of cells: eosinophilic granulocytes, primitive hemocytoblasts (‘amebocytes’), and modified hemocytoblasts. The latter suggest a specialized blood corpuscle, but represent apparently only a stage in the dissolution of intravascular hemocytoblasts. These ‘corpuscles’ have the form of flattened lenticular discs, approximately 12 μ in diameter. The eosinophils differentiate extravascularly from hemocytoblasts. The hemocytoblasts are in part free parenchymal cells, in part they arise from a bilaterally paired ‘lymphogenous organ’ or ‘blood island’ associated with the lateral vascular channels at the level where the ceca diverge from the esophagus.
Some ultraviolet photomicrographs made with different wave lengths
Authors: Wyckoff Ralph W. G. , Ebeling Albert H. 
Published: February 2005

AbstractPhotomicrographs have been made of grasshopper spermatocytes using ultraviolet light of several wave lengths. For studying chromosomes this wave length should be between ca 2800 A and ca 2500 A. With higher frequencies the entire cell becomes strongly absorbing and relatively little detail is to be seen. All cell structures, including the chromosomes, are as transparent to λ = 3500 A and to longer ultraviolet waves as they are to visible light. The present experiments do not indicate the exact point between λ = 3500 A and λ = 2800 A at which the selective chromatin absorption commences.
Studies on the morphology of tritrichomonas foetus (Riedmüller) (protozoa, flagellata) from American cows
Authors: Wenrich D. H. , Emmerson M. A. 
Published: February 2005

AbstractTritrichomonas foetus (Riedmüller) which occurs in the genital tract of domestic cows and which appears to be associated with pathological conditions, including sterility and abortion, has been found in American cows and its morphology studied.The spindle‐shaped body is 10 to 25 μ in length and bears three anterior flagella and a posterior flagellum which constitutes the marginal filament of the nearly full‐length undulating membrane and continues posteriorly as a trailing flagellum. There is an accessory filament in the undulating membrane. The axostyle is of the thick, hyaline type and contains endoaxostylar granules in the capitulum and bears a chromatic ring at the point of emergence from the body. There is a well‐developed costa under the undulating membrane and a simple type of parabasal body.In its morphology this species more nearly resembles such intestinal forms as T. augusta and T. muris than it does Trichomonas vaginalis of man, since the latter has four anterior flagella, a short undulating membrane without an accessory filament, no trailing flagellum, a different type of axostyle, and a parabasal filament along with its larger parabasal body.
The effect of x‐rays upon the chromosomes of circotettix verruculatus (orthoptera)
Authors: Helwig Edwin R. 
Published: February 2005

AbstractX‐rays produce fragmentations of the chromosome commonly in the region of fiber attachment.Fiberless fragments become attached to other chromosomes or those portions of them that retain fiber attachments. Thus, chromosomes homologous to parts of two other chromosomes are produced and at synapsis multiples are formed. Such multiples are chains or closed‐circles depending upon whether a single or a reciprocal translocation respectively has occurred. Sometimes entire chromosomes unite to form a multiple. In general, the multiples divide so that the segregation of homologous elements is complete. However, sometimes the separation of homologous portions is impossible and, then, gametes which contain sectional‐duplications, or sectional‐deficiencies, or both, are produced. Any two or more chromosomes may be involved in multiple formation although the larger elements are more frequently implicated.Translocations may occur between homologues resulting in an unequal division of chromatin.The locus of fiber attachment (acromite) is an integral part of a chromosome and its loss to one homologue causes non‐disjunction or other inequalities in the distribution of the chromatin.Supernumerary chromosomes are frequently present in the spermatocytes.Homologues unaccountably sometimes fail to synapse in the descendants of irradiated cells.There is a striking similarity between natural and induced chromosomal aberrations as well as a correlation between the distribution of radioactive minerals and naturally occurring aberrations.
Chromosome studies in stauroderus (an orthopteron)
Authors: Corey H. Irene 
Published: February 2005

AbstractS. scalaris (Orthoptera, Truxalinae) from Scotland and Siberia has a diploid complex of seventeen chromosomes (six V‐multiples and eleven rods). Each element possesses a polar or proximal granule recognizable throughout all stages of prophase of the first spermatocyte and in all other stages when concentration is not so great as to mask it. In telophase of the first spermatogonial division the polar granules may fuse into a single body or into several irregular bodies (chromoplasts of Eisen and Janssens). By the end of the diatene stage the chromoplast is completely resolved into its component granules which are clearly recognizable as the proximal parts of the rods (ends) and of the multiples (mid‐portions). The accessory chromosome is precocious in its behavior and differential in structure at all stages, but its peculiarities are most marked in metaphase of the first spermatocyte where it becomes a non‐chromatic vesicle with peripheral granules and chromatic core. Each multiple arises from the permanent fusion of two rod elements. They differ from those in other members of the same sub‐family in diakinesis (eight‐strand or octad stage) in that proximal concentration extends almost throughout the multiple.