bluuebunny/crossref_metadata_2025 huggingface dataset:
A histological study of the colic caeca in the bantam fowl
Authors: Looper James Burdine , Looper Margaret Haase
Published: February 2005

The caeca of fourteen bantam fowls have been studied. These fowls ranged in age from six days' incubation to three years after hatching. Between the fifth and sixth days of incubation rectal caeca arise as evaginations from the intestine at the junction of the ileum with the colon. The develoing caeca closely resemble histologically the intestine to which they are attached.

The caeca are essentially devoid of content until about the nineteenth day of incubation, but during the remaining days of incubation are gorged with a bluish‐gray material similar to that found in the colon. Thus, an early defecatory function is indicated.

In general, the proximal third of the caeca remains histologically similar to the intestine, but the distal two‐thirds undergoes regression. The latter involves the atrophy of the epithelium and glands, accompanied by the appearance of lymphoid tissue. Much of the lymphoid tissue eventually disappears, to a large extent by atrophy and dissolution of the leukocytes. However, to some extent, lymphocytes develop into granulocytes which escape with other leukocytes into the lumina of the caeca and there disintegrate.

Lymph nodules begin to appear in the caeca about one week after the chick hatches. The leukocytes, at least in part, arise in situ from the reticular stroma. Eosinophils arise in certain areas of the tunica propria, and in the earlier stages of their development resemble large lymphocytes, in the cytoplasm of which basophilic, amphophilic, and acidophilic granules are intermingled.
Cytoplasmic inclusions of Trichamoeba and their reaction to vital dyes and to osmic and silver impregnation
Authors: Hall Richard P.
Published: February 2005

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.
Studies on some physiological functions and morphological characters of Rhabditis (Rhabditidae, nematodes)
Authors: Chitwood B. G.
Published: February 2005

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.
The germ cells in the hermaphroditic gland of Polygyra appressa
Authors: Pennypacker Miriam I.
Published: February 2005

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.
Cytoplasmic phenomena in the spermatogenesis of gerris
Authors: Pollister Arthur W.
Published: February 2005

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.
The human ovarian germ cells
Authors: Swezy Olive , Evans Herbert M.
Published: February 2005

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.
Studies on the comparative histology of the digestive tube of certain teleost fishes. I. A predaceous fish, the sea bass (Centropristes striatus)
Authors: Blake Irving H.
Published: February 2005

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.
The life history of Cryptocotyle lingua (Creplin), with notes on the physiology of the metacercariae
Authors: Stunkard H. W.
Published: February 2005

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.
The development of the ear of Acanthias vulgaris
Authors: Quiring D. P.
Published: February 2005

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.
The cytology of several species of iceryine coccids, with special reference to parthenogenesis and haploidy
Authors: Hughes‐Schrader Sally
Published: February 2005

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.
The labyrinth of bufo vulgaris japonicus larva. Especially, upon the morphologic study of the perilymphatic space, in connection with the membranous labyrinth and auditory capsule
Authors: Amano Kageyas W.
Published: February 2005

A morphologic study of the labyrinth, especially on the perilymphatic space with its physiologic aspect, is presented in this paper. The perilymphatic space starts its development with the chondrification of the auditory capsule, and is completed by the end of the first third of metamorphosis. The author divides the whole spatium into two parts: the ductus perilymphaticus et diverticula and the pars spongiosa spati perilymphatici. The ductus perilymphaticus et diverticula may play an important rǒle in carrying out the functions of both equilibrium and audition. The pars spongiosa serves not only to fasten the membranous labyrinth to the capsular wall, but acts as a safeguard for the functions of both the membranous labyrinth and the ductus perilymphaticus et diverticula. The ductus system may have more important physiologic relations than does the membranous labyrinth in connection with the cranial cavity and spinal cord, as to the change of pressure, the transmission of vibrations, the osmosis of fluids, etc. A number of microscopic and schematic figures are shown with reference to the anatomic and morphologic relations of the membranous labyrinth, auditory capsule, and spatium perilymphaticum.
The spermiogenesis of Succinea ovalis say, with special reference to the components of the sperm
Authors: Hickman Cleveland P.
Published: February 2005

An investigation of the spermiogenesis of Succinea ovalis Say, a small terrestrial pulmonate, has revealed: 1) The germ cells are differentiated from indifferent germinal epithelial cells. In this form the germinal epithelium is a true epithelium, and not a syncytium. 2) Forty chromosomes are found in the spermatogonial divisions and twenty in the maturation divisions. 3) Early in spermiogenesis the proximal centriole penetrates through the spermatid nucleus and, with the oxychromatin, forms an intranuclear rod similar to that reported for certain prosobranches. The homology and significance of the rod are discussed. 4) Of the cytoplasmic structures, the mitochondria and the Golgi apparatus were followed through all stages of spermatogenesis. 5) At the maturation divisions the mitochondria are grouped into peculiar. thread‐like structures. Some of the mitochondria take part in the formation of the sheath around the axial filament of the spermatozoon, while the remainder are sloughed off with the cytoplasmic remnant. 6) The Golgi apparatus consists of a number of banana‐shaped rods closely grouped around the idiosome. Three to five Golgi rods are found in the spermatid stages. A portion of the Golgi apparatus and idisome (acroblast) forms the acrosome, and the Golgi remnant is discarded at the end of spermatogenesis. 7) In mature sperm both head and tail have a spiral structure. The origin and nature of the spirals are pointed out.
The history of the germ cells in the viviparous teleost platypoecilus maculatus
Authors: Wolf Louis E.
Published: February 2005

This study is based upon a series of ontogenetic stages from just before coelom formation to maturity.

Primordial germ ceils are first seen at the outer edge of the lateral mesoderm and are traced from there to a position in the genital analagen. Counts indicate that most of them succeed in reaching the genital anlagen, where they from definitive reproductive cells in both sexes.

The evidence seems to show that there is some transformation of somatic cells into germ cells in the immature female, but that this transformation is not extensive. In the male the primordial germ cells are the sole source of the definitive elements.
The intranuclear deutoplsm and the origin of gametes in the turbellarian Prorhynchus applanatus Kennel
Authors: Jones E. Ruffin
Published: February 2005

It is shown that in Prorhynchus applanatus there exists a type of yolk elaboration which has hitherto not been reported. Formation is within the nucleus through the growth and fusion of nucleoli, but the yolk globule becomes larger than the original nucleolus. The developing individual utilizes the food material contained in the yolk cells in the following order: (1) cytoplasm of the yolk cell, (2) yolk bodies contained in this cytoplasm, (3) intranuclear yolk, (4) nucleoplasm. It is also shown that the germ cells in this form arise from the endoderm by diapedesis, but that the yolk cells are mesenchymal in origin. The sequence of formation of male and female gametes precludes the possibility of the presence of sex hormones such as are found in higher forms.
Vertebrate cephalogenesis. VI. A. The velum—its in head building—the hyoid. The Velata. The origin of the vertebrate head skeleton. B. Myxinoid characters inherited by the teleostomi
Authors: Ayers Howard
Published: February 2005

The oldest parts of the fibrous, cartilaginous, and bony head skeleton of vertebrates descend from the amphioxid ancestors of the myxinoid fishes. The skeleton of the velum and jaw bars of the amphioxids transform into the jaw apparatus and hyoid‐velar head skeleton of the myxinoids, and some parts are passed on by inheritance to the teleostome fishes (sturgeons). These anatomical characters prove descent with modification. The theory of the origin of jaws and hyoid from branchial cartilages is not supported by the facts, as both jaws and hyoid structures were developed long before branchial cartilages furnished material for head building. The Velata, the oldest of living vertebrates, include the amphioxids and marsipobranchs, and are marked off from the higher forms by the important organ, the velum, which separates the prebranchial from the branchial head. A remnant of the velum inherited by all of the higher vertebrates is the hyoid mechanism—an important anatomical landmark.
Polymorphism among the subgenera of nasutitermes
Authors: Hare L.
Published: February 2005

This study is concerned with the interrelationship existing among the polymorphie soldier castes of six representative subgenera of the genus Nasutitermes. By measurements of anatomical parts and camera‐lucida drawings, an attempt has been made to compare these particular subgenera on a basis of gradual divergence of certain structures. For this purpose a series of tables was compiled in which apparently unstable structures were compared to a relatively stable figure in all available species of the selected subgenera.

According to my findings, it was concluded that there is no strict correspondence between the major, intermediate, and minor castes of different subgenera of the genus Nasutitermes. Particular reference is made to the work of N. Holmgren ('12) and to that of J. S. Huxley on heterogonic growth.
The histology of posterior regeneration in the polychaete Chaetopterus variopedatus
Authors: Faulkner G. H.
Published: February 2005

After amputation, the wound is closed by the protrusion and lateral expansion of the alimentary canal over the cut muscles and its final fusion with the epidermis laterally after about twenty‐four hours. Associated with the expansion is a divergence of the two adjacent halves of the ventral nerve cord in the last remaining segment. As a result, the whole of the new regenerated lobe behind the ring of the cut epidermis is interneural; i.e., it is an enlargement of the normally small area separating the two nerve cords. Undifferentiated cells, or neuroblasts, are normally located interneurally, and during regeneration these neoblasts proliferate throughout the enlarged interneural zone of the papilla and migrate throughout the lobe. At first the neoblastic mesenchyme filling the lobe is loose and homogeneous, but as the cells settle down against the outer wall they replace the old intestinal cells and assume the characters of new epidermis. Internally, the mass acquires paired cavities, while the cells surrounding the cavities differentiate into muscle, peritoneum, etc. Thus one type of cell gives rise to the whole of the regenerated papilla. These cells are also the mother cells of the gametocytes.
The chondrocranium of a 23‐mm. necturus
Authors: Shumway Waldo , Webb Richard L.
Published: February 2005

This study is based on a wax model reconstructed from serial sections stained with basic fuchsin and picro‐indigo‐carmine. It shows: 1) that the columna ethmoidalis and planum basale are chondrified at this stage; 2) that a cartilaginous antorbital process is present; 3) that the stapedial plate is cut out from the wall of the otic capsule; 4) that the so‐called crista trabecularis is an independent element homologous with the sphenolateralis of the Anura; 5) that the fourth visceral arch is not present and that the fifth is still in the precartilaginous stage; and, 7) that there is no evidence that a pro‐occipital vertebra is formed.
Observations on the life history of a fingernail shell of the genus Sphaerium
Authors: Foster Thural Dale
Published: February 2005

By statistical analysis and microscopical examination of a series of monthly quantitative collections, an attempt has been made to interpret the life history and reproductive habits of Sphaerium solidulum, one of the numerous species of the genus Sphaerium.

Individuals of the species under observation have a distinctly limited life span of approximately one year. The period of maximum reproduction of this species does not occur in the summer months, as previously believed, but in the winter months. Seasonal growth rings are not present on this shell, although concentric lines are characteristic. No individuals of maximum size were present during the months from August to February. Maximum‐size adults are apparently sterile. The analysis of distribution curves of each quantitative sample indicates two size groups in each collection as shown by the bimodal character of each graph. Distribution curves of embryos feature the bimodal character of the young and adult. The conclusions are founded on data secured from twelve monthly collections made from the same habitat totaling 7022 individuals.
The development of the prechordal plate and mesoderm of amblystoma punctatum
Authors: Adelmann Howard B.
Published: February 2005

This paper describes the development of the prechordal plate and mesoderm of Amblystoma punctatum from the late yolk‐plug stage to the stage of about nineteen somites.

In the earliest stage described the prechordal plate is embedded in the roof of the archenteron and flanked on both sides by prechordal mesoderm with which it is fused. The characteristics and limits of the prechordal plate and mesoderm are discussed and the fate of both traced. It is demonstrated that the mesodermal cores of the mandibular arches are probably largely derived from the prechordal mesoderm which flanks the prechordal plate. The prechordal plate is later separated out of the roof of the foregut in a caudocephalic direction, giving rise to a median mass of mesoderm which expands laterally independently of the mandibular portions of the prechordal mesoderm to give rise to head mesenchyme lying largely anterior to the level of the hyoid arch. The expansion of this mesoderm is followed in some detail.

The boundary between prechordal and notochordal regions is placed at approximately the boundary between the mandibular and hyoid arches.

The question of the interpretation of the prechordal region is briefly discussed.
The embryology of amphioxus
Authors: Conklin Edwin Grant
Published: February 2005

Although the egg of Amphioxus is much more fluid and less stereotyped than that of Ascidians, the poles, axes, and localizations of formative materials are much the same in the two. The spermatozoon enters near the vegetative pole and a peripheral layer of granular cytoplasm flows to this pole and later forms a crescent around the posterior side parallel to the first cleavage amphiaster; this is the mesodermal crescent. On the anterior side a similar area later gives rise to the chorda‐neural crescent. Above these crescents is the ectodermal area, below them the endodermal area. The early cleavages divide these crescents and areas just as in Ascidians. The coeloblastula is at first spherical, but later flattens in the region of the mesodermal crescent; this flattening extends forward on the vegetative side to the chorda‐neural crescent, where the invagination is sharpest. The blastopore is at first triangular in outline, the dorsal lip being formed by the chorda‐neural crescent and the lateral lips by the mesodermal crescent. Later the chorda and the mesodermal crescents are infolded, the lateral lips fuse to form the ventral lip which grows dorsalward, the blastopore becomes wider from right to left than dorsoventrally, the gastrula elongates and in the angles between dorsal and ventral lips the mesodermal crescent forms the mesodermal grooves in the lateral walls of the gastrocoel.
Observations upon the American representative of macrostomum tuba
Authors: Kepner William A. , Stiff M. W.
Published: February 2005

What appears to be a variety of Macrostomum tuba has been described in this paper. There is but a single retinula in each eye. This visual cell displays three regions: rhabdome, ellipsoid, and myoid, as does a vertebrate's retinula. Moreover, the accessory pigment associated with the retinula of M. tuba is applied to the rhabdome and not to the ellipsoid and myoid; this likewise is similar to the distribution of the pigment about the vertebrate's retinula. An analogy, therefore, may be drawn between the visual cell of the rhabdocoele and that of the vertebrate. This is so strong as to suggest homology. Several features peculiar to this variety are: first, the chitinous, distal ring of the penis; second, the fact that shell and yolk droplets seem to be elaborated by each cell destined to become an oocyte.
Comparative cytochemical studies by micro‐incineration of a saprozoic and an holozoic infusorian
Authors: Horning E. S. , Scott Gordon H.
Published: February 2005

Nyctotherus cordiformis and Opalinids infesting Rana pipiens were studied by microincineration and in stained control sections. A marked difference in concentration and distribution of mineral salts was noted within saprozoic and holozoic organisms. The endoplasm in the saprozoic protozoa was free from inorganic residue except for the ‘vegetative’ granules; the protoplasm of the holozoic infusorians consisted of a fine network of mineral salts. Detailed examinations suggested that the qualitative and quantitative differences might be correlated with diffusion of digestible material through the cuticle. The inorganic residue of the walls of vacuoles was relatively rich in iron.
Histology of the fresh‐water mussel heart with reference to its physiological reactions
Authors: Motley Hurley Lee
Published: February 2005

The anatomical isolation of the auricles from the ventricle in hearts of fresh‐water mussels representing nine North American species has been confirmed. The muscle fibers in these hearts without exceptions were found to be of the smooth, unstriated type. Bundles of these fibers loosely interwoven, form the thin, delicate, heart wall, which contains many sinus‐like spaces. The outside portion of the heart wall exposed to the pericardial fluid is covered with a definite epicardium composed of a single, dense layer of epithelial and scattering mucous cells. The inside of the heart cavity has no endocardium, the muscle fibers being in direct contact with the blood. No special conduction tissue, nerves or ganglia were found in the heart wall. Correlations of these anatomical and histological findings with the physiological reactions of the living heart in situ are made, and the mechanical and chemical control of the heart discussed.
Sex cycles and other cyclic phenomena in a chimpanzee during adolescence, maturity, and pregnancy
Authors: Tinklepaugh O. L.
Published: February 2005

The sex cycles of a chimpanzee were studied for 18 months, during which the animal matured, menstruated four times, conceived, and delivered.

Pronounced swelling of the ano‐genital region appeared periodically prior to the first menstruation. During menstrual cycles the swelling endured during most of the period between flows. Genital swelling was always accompanied by estrus; copulation and insemination never occurred during its absence.

The animal was alert and active when in estrus, demonstrated non‐sexual affection for the male just prior to the flow, and appeared to be physically distressed during the first days of each flow.

There were periodic weight changes coordinated with the animal's menstrual cycles.

During pregnancy menstruation ceased, but genital swelling, with accompanying sexual receptivity, continued in irregular cycles.

Cyclic changes in the desquamation of the vaginal epithelium occurred during menstrual cycles, were absent during pregnancy.

The gestation period was approximately 246 days. At death from puerperal sepsis, 15 days after delivery, the ovaries were in a restin stage, one of them bearing a degenerating corpus luteum.

The evidence given indicates that sex‐skin swelling and estrus are similarly controlled, but may occur independently of menstruation, cornification of the vaginal epithelium, or ovulation.
Studies in living tissue
Authors: Baumgartner W. J.
Published: February 2005

A survey of biological literature of the present reveals a tendency to turn to the study of the living cells and tissues. This tendency is indicated by the use of microdissection, ultraviolet microscopes, transparent chambers in rabbits' ears, growing nerve cells and fibers in tailfins of amphibian larvae, and by intravitam technic on insect germ cells. The division stages of the germ cells of Anasa tristis which were carefully studied and drawn thirty‐odd years ago are now shown by actual unretouched photomicrographs. These photomicrographs confirm the drawings in many points and show other structures such as mitochondria even more clearly than the drawings do. An account of a peculiarly shaped spermatozoon which has not been described heretofore in the literature is added. The question of the great variations of shapes of spermatozoa is discussed. The advantages of the use of methods for studying living cells, especially of intravitam technic, is emphasized.
The effects of bilateral and unilateral castration on the epididymis, with special reference to the mitochondria‐Golgi complex
Authors: Winters Laurence M.
Published: February 2005

Rats in different stages of maturity were castrated in pairs–bilaterally and unilaterally–with respect to the effects upon the epipidymis. The epididymis was also studied during its developmental stages. A special study was made of the mitochondria and Golgi materials; and a comprehensive review of the literature is included.

Bilateral castration was followed by a marked regression of functional activity on the part of the epithelial cells of the epididymis. Unilateral castration produced no similar change. The mitochondria‐Golgi complex in the epithelial cells of the epididymis was reduced decidedly following bilateral castration; while unilateral castration had no visible effect upon these materials. The mitochondria‐Golgi complex increased and decreased in amounts in keeping with the state of secretory activity of the epithelial cells.

Golgi nets were found within the lumina of the tubules. Granules within the cells and the tubules were colored with osmic acid, Altmann's anilin acid‐fuchsin, iron hematoxylin, or acid fuchsin‐orange G. Osmic acid impregnation was removed from granules and nets and Altmann's anilin acid‐fuchsin stain put in its place.

It is believed that mitochondria and Golgi materials are very similar and furthermore that they are secretory products of the cells. It is also believed that the state of development of the mitochondria‐Golgi complex is an indication of the functional state of the epithelial cells of the epididymis.
Studies on the spermatocyte divisions in ascaris megalocephala; with special reference to the central bodies, Golgi complex and mitochondria
Authors: Sturdivant H. P.
Published: February 2005

The centrioles are recognized early in the prophase of the primary spermatocyte. They soon become double and migrate around the nucleus in opposite directions. As this is completed the nuclear membrane breaks down and spindle fibers appear. The centrioles divide in the metaphase at a time when the centrosome is still perfectly spherical. The centrosome divides in the anaphase, giving the two centers for the second division. The centriole disappears in the spermatid and cannot be seen in later stages. The behavior of the centers during the spermatocyte divisions is strikingly like that of the egg centers and other types of mitoses. Therefore, it is concluded that the centrioles of the spermatocytes are not to be regarded as different from the centrioles in other types of mitoses.

The Golgi bodies increase in number and size during the growth period of the cell. They are usually found in the shape of rings. From these rings are produced the refringent granules which fuse in the late spermatid to form those of the mature sperm. It is therefore concluded that this process represents the formation of the acrosome. The mitochondria show little change during the maturation divisions. In the late spermatid they aggregate around the nucleus and become vesiculated. This is interpreted as the formation of the prenebenkern.
The segregation of the germ cells in the grasshopper, Melanoplus differentialis (acrididae; orthoptera)
Authors: Nelsen Olin E.
Published: February 2005

The segregation of the germ cells is related in time and differentiation to the ectoderm (ventral plate), the inner germ‐band layer (lower layer) and the mesenteron (entoderm) rudiments. The inner germ‐band layer is formed by invagination of cells from a median blastoporic groove and by cellular proliferations among the invaginating cells and from the median line of the ectoderm immediately caudad of the blastoporic groove. The mesenteron material is derived from inner germ‐band layer material associated with the internal ends of the stomodaeum and proctodaeum. The germ cells are segregated from the lateral margins of the abdominal lobe ectoderm in the region of the amnion attachment as segmentation of the abdominal lobe is initiated. They ultimately become separated from the ectoderm cells of the lateral wall and from the amnion and migrate in a passive manner onto the coelomic sacs where they become associated with the inner walls of the sacs. When the coelomic sacs unite the germ cells and the splanchnic wall mesoderm cells form two continuous cell strands from the first to the eighth abdominal segments, inclusive. These strands form the indifferent genital rudiments. An endeavor is made to correlate the segregation of the germ cells in the grasshopper with that of various other insects.
The distribution of chitin in an insect
Authors: Tauber Oscar E.
Published: February 2005

By treating the clean skeletal tissue of an insect with concentrated KOH at 160° C., the contained chitin is converted to chitosan, and all pigmentation and admixtures are removed. The per cent distribution of chitin, expressed as chitosan, in the exoskeleton of the cockroach, Periplaneta fuliginosa, ranges from 37.65 in the dorsal abdomen to 18.22 in the hindwings. Other regions contain the following per cents: ventral abdomen, 37.11; metathoracic legs, 35.55; mesothoracic legs, 33.28; prothoracic legs, 32.24; pronotum, 31.55; head, 31.07; genitalia, 29.28; dorsal thorax, 29.07; ventral thorax, 28.33; antennae, 27.77; cerci, 25.65; and forewings, 19.99. Regional variations are constant in different individuals of the same species. The crop and gizzard contain 18.69 per cent; the hindgut, 18.15 per cent. The remainder of the alimentary tract contains no chitin. Traces of chitin are found in the trachea. No chitin is found in the egg‐cases of this species. No correlation between chitin content and pigmentation or hardness is shown. Based on results from three trials, using thirty insects, the per cent of chitosan in the clean, dry chitinous material from the entire animal is 29.60; the per cent of chitosan based on the weight of the live animal averages 2.01.
Localization of mineral ash in the organelles of trichonympha, a hypermastigote flagellate from zootermopsis angusticollis
Authors: Maclennan R. F. , Murer H. K.
Published: February 2005

The three species of Trichonympha found in Zootermopsis angusticollis were studied by micro‐incineration, by control sections, and by Macallum's methods for iron and calcium. The mineral ash is concentrated in the neuromotor system, chromatin, nuclear membrane, the posterior end where ingestion takes place, and in cytoplasmic granules. Micro‐incineration and Macallum's Prussian blue method reveal iron in the chromatin alone; Macallum's haematoxylin gives a positive test for iron in the chromatin, rostrum, neuromotor fibrils, etc. It probably is not as specific as the other methods. The two staining methods give negative tests for iron except after acid hydrolysis. Calcium is present in the chromatin, neuromotor system, posterior region of the body, and in many endoplasmic granules. The localization of calcium is correlated with the localization of normally gelated regions.
Caste determination and differentiation with special reference to the genus reticulitermes (Isoptera)
Authors: Hare Laura
Published: February 2005

The results of recent investigations concerning caste determination among termites have been briefly reviewed with emphasis upon the work of Thompson ('17). From examination of new data upon the development of Reticulitermes arenincola Goellner, R. flavipes (Kollar), and R. tibialis Banks, and of Thompson's original R. flavipes material, I am unable to substantiate her claim that the sterile and reproductive castes are separable into two distinct groups at the time of hatching. I could distinguish them first in stadium three and suggest that the second stadium may be a critical period in differentiation. From evidence to date, it must be granted that both intrinsic and extrinsic factors may play a role in the production of castes. The delay in appearance of demonstrable caste differences until the third stadium in the genus Reticulitermes at least admits of an opportunity for extrinsic factors to be effective. Growth and metamorphosis of various structures which ultimately lead to the three differentiated castes have been followed through successive stadia. Gynandromorphs and intercastes among social insects give indication of the physiological and genetic factors influencing both morphological and behavior differences among castes.
The effects of vitamin E deficiency on the testis of the male fowl (Gallus domesticus)
Authors: Adamstone F. B. , Card L. E.
Published: February 2005

The effects of vitamin E deficiency in the fowl were observed in Rhode Island Red males over a period of approximately 2 years.

Mating experiments showed that after 1 year on the E‐free diet all of the males were capable of fertilizing ova, but that after 2 years some of the males were sterile.

Sperm smears showed that shortly after the beginning of the experiment, many of the mature spermatozoa exhibited an abnormal condition of the nuclear material of the head, while others remained normal.

In histological sections of the testes made at the end of the 2 years, conditions varied from almost normal to complete atrophy, the latter being a condition that has already been described in the male mammal. Moreover, the conditions in any given section were not uniform for even in an advanced stage of E deficiency there were small islands of apparently normal tissue. However, in this case, as in the mammal, the process of degeneration affects the mature sperm cells first and gradually works to the outside of the seminiferous tubule thus attacking the youngest maturation stages last.

The results of the experiment point definitely to destruction of the testis under prolonged E‐deficient conditions but it is also quite apparent that the testis of the fowl is extremely resistant to vitamin E deficiency.
A cytological study on the liver of the rat, with special reference to the ‘intracellular blood canaliculi,’ inter‐ and intracellular bile canaliculi, mitochondria and Golgi apparatus
Authors: Jay Edith M.
Published: February 2005

In sections from livers injected through the vascular system with Carter's carminegelatin or Berlin‐blue gelatin masses at known, constant pressures, many cells were observed to contain ovoid or spherical bodies of the colored injection masses, similar to those described by Schäfer and his students, Herring and Simpson, as intracellular blood canaliculi.' In these livers practically all the cells were vacuolated. However, with livers injected with Berlin‐blue gelatin mass dissolved in Locke's solution instead of distilled water, there were no intracellular masses and the cells appeared normal, though the sinusoids were completely filled with injection mass. The so‐called ‘intracellular blood canaliculi’ described by Schäfer are interpreted as artefacts produced by a combination of factors, the most important of which is the difference in osmotic pressure. This is produced by the hypotonicity of the injection masses that are usually used, augmented perhaps by the effect of mechanical pressure used in administering the injection mass.

Following impregnation of liver tissue by Golgi's rapid method, the usual network of intercellular bile canaliculi was revealed, but the presence of a permanent system of intracellular canaliculi was not observed. A few short, knobbed intracellular projections from the intercellular bile canaliculi were noticed; these probably represent the passage of secretion material into the intercellular bile canaliculi at the moment of excretion.
Maxillary breathing valves in the sharks Chlamydoselachus and Cetorhinus with notes on breathing valves in thirteen marine teleosts
Authors: Gudger E. W.
Published: February 2005

Chlamydoselachus anguineus has, extending across the upper front mouth just behind the origin of the rear teeth of each row, a shelf of tissue forming a functional breathing valve. Valves of three types were found in five specimens. One has the hinder edge crescentic, another is like the head of a ‘broad arrow,’ and the third is intermediate in outline. A similar valve, crescentic in outline has been found in the upper front mouth of a 13‐foot specimen of Cetorhinus maximus dissected in the American Museum.

Breathing valves are briefly described in thirteen marine teleosts at Tortugas, Florida. Some fishes had only maxillary valves, some mandibular, and a few had both. These consist of thin folds of tissue which swing back and forth as the fish breathes. A brief summary is given of breathing valves in other teleosts and in sharks and rays.

The function of breathing valves in fishes is to prevent regurgitation of water during expiration as the fish swims along with partly open mouth. It is also correlated with feeding where the food is impaled on the teeth and held for swallowing, or where the fish feeds on pelagic organisms collected by swimming along with open mouth.
Abnormalities in flatfishes (heterosomata) I. Reversal of sides a comparative study of the known data
Authors: Gudger E. W.
Published: February 2005

Flatfishes lying on one side and that blind and colorless, but having the upper side two‐eyed and colored are abnormal fishes which in their own group are perfectly normal. Some normally lie right side up (dextral) others point left (sinistral). Any departure from these normal conditions constitutes such a specimen an abnormal flatfish. The simplest departure is reversal‐i.e., a normal dextral fish lies on its right side and points left and vice‐versa. Sixteen reversed fishes have been described, but in various species from 3 to 100 per cent reversals have been noted.

Reversal might be thought dependent on the structure of the optic chiasma. The Psettodidae (lowest family) have a dimorphic chiasma (right or left nerve dorsal) and are indifferently dextral or sinistral. But the dextral Soleidae and the sinistral Cynoglossidae (highest families) have dimorphic chiasmas with only five recorded reversals. In between, the monomorphic sinistral Bothidae have the right nerve dorsal even in the five indifferent species. And the monomorphic dextral Pleuronectidae include three indifferent species (one having up to 100 per cent reversed) with the left nerve dorsal even in reversed fish. The explanation of reversal must be found in genetics.
The lymphatic system of the snake
Authors: Conklin Ruth E.
Published: February 2005

The anatomy of the lymphatic system of the snake is described, together with some preliminary observations of the blood vascular system. Lymphatic vessels are numerous and thin‐walled, chiefly periangious, but some are in close relation to the vertebral, column. The aortic lymphatic enlarges to form a sac in the abdominal region which encloses several of the viscera and in many cases communicates with their connective tissue sheaths. Lymph vessels in the skin and body musculature form a regularly arranged segmental network. The system communicates with the blood vascular system in two places: by means of a pair of posterior lymph hearts in the region of the cloaca, and at the jugular lymph sac just craniad to the heart. The arrangement and distribution of lymphatic structures is of interest in relation to phylogenetic development and because of the specialization of structure due to the elongate form of the snake.
Morphology and development of the femoral chordotonal organs of melanoplus differentialis (orthoptera, acrididae)
Authors: Slifer Eleanor H.
Published: February 2005

Chordotonal organs are present in the prothoracic, mesothoracic and metathoracic femora of Melanoplus differentialis. These have been described and their development traced from ectodermal invaginations located at the proximal and distal ends of the prothoracic and mesothoracic and at the distal end of the metathoracic femora of the embryo.