bluuebunny/crossref_metadata_2025 huggingface dataset:
Scanning electron microscopy of the capillary loops in the dermal papillae of the hand in primates, including man
Authors: Ikeda Akira , Umeda Naoto , Tsuda Kuniyoshi , Ohta Shigeo
Published: February 2005

The microvasculature of the skin of the hand in primates, including man, was examined by means of scanning electron microscopy of corrosion casts. In this study, the microvascular patterns and structures in different areas of the hand, and the changes in vascular patterns that occur with age, have been described.

The typical structure of the capillary loops in the hand can be observed in the ball of the finger of the young adult monkey. The capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papillae, and these became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other to form the primary and secondary venous arcades. The secondary venous arcades anastomosed with each other and flowed into the subpapillary venules, which run along the dermal furrow in the fingerprint.

Changes in vascular patterns with age could be observed. In the infant fingerprint, the vascular systems had not yet differentiated, especially the venous system in the dermis. In the old adult finger, the capillary loops presented complicated features deviating due to aging.
Technique for preparing cross‐section transmission electron microscope specimens from ion‐irradiated ceramics
Authors: Zinkle S. J. , Haltom C. P. , Jenkins L. C. , DuBose C. K. H.
Published: February 2005

The general techniques necessary to produce a high‐quality cross‐sectioned ceramic specimen for transmission electron microscope observation are outlined. A particularly important point is that the width of the glued region between faces of the ceramic specimen must be < 0.2 μm to prevent loss of the near‐surface region during ion milling. A recently developed vise for gluing ceramic cross‐section specimens is described, and some examples of the effect of glue thickness on specimen quality are shown.
Dry fracturing and cutting for techniques for scanning electron microscopy of poly‐vinyl chloride particles: Application to internal structure observations
Authors: Yañez Maria Julia , De Lozano Viviana Sorrivas
Published: February 2005

Two methods for examining the internal structure of poly‐vinyl chloride (PVC) particles are described. Very small PVC particles, polymerized by the emulsion process, were mounted on an aluminium adhesive tape and pressed with a similar tape. Both tapes were then pulled apart so that the specimen was broken in two fractions, which were observed by scanning electron microscopy. On the other hand, bigger PVC particles manufactured by following the suspension polymerization process, were frozen and hand sectioned with a razor blade under liquid nitrogen vapor. The results were highly satisfactory. These methods were easy to implement, the cost of materials for sample preparation was negligible, and they offered the ability to obtain multiple information from a single sample.
The somatic chromosomes of the opossum (Didelphis virginiana)
Authors: Hoy William E. , George W. C.
Published: February 2005

There are eleven pairs of chromosomes in the somatic cells of the opossum.

The sex chromosomes are of the x‐x type in the female and the x‐y type in the male.

The number and type of the chromosomes are constant in the wide variety of tissues and organs studied, except that one dividing giant cell of the spleen showed an 8n number of chromosomes.

The arrangement of the chromosomes in equatorial plates is that of an autosomal ring surrounding the centrally located sex chromosomes.
An embryological study of a special strain of deformed x‐rayed mice, with special reference to the etiology and morphogenesis of the abnormalities
Authors: Plagens George M.
Published: February 2005

This investigation consists of an extensive histological study of a special strain of abnormal x‐rayed mice, in an attempt to determine the embryonic origin and development of certain congenital abnormalities that are hereditary.

The study shows that development of the x‐rayed strain is normal up to the thirteenth day after insemination, after which pathological structures appear in the form of blebs, hematomas, and thrombi. As a result of the formation of the blebs and hematomas a general condition is set up within the embryo which resembles that of thrombosis. The thrombi when formed exert a mechanical effect by crowding out the normal tissue. A chemical effect is also produced by the blood cells and fluid extravasated from the thrombus which penetrate into the forming tissues resulting in their perverted development. Thus the thrombi are the immediate factors causing the various regions of the body to be deformed.
The opercular apparatus of salamanders
Authors: Monath Thomas
Published: February 2005

The primitive structure of the salamander otic capsule (exemplified by Hynobius) includes both operculum and columella in the fenestra vestibuli and connection of operculum with suprascapsular cartilage by an “opercularis” muscle formed by levator scapulae. Larvae of Hynobiidae, Ambystomatidae, and Salamandridae have early development of columella and stilus, which are used in sound transmission via the suspensorium until the development of the operculum and its muscular connection with the shoulder girdle at metamorphosis. Hynobiids and ambystomatids show parallel trends toward reduction or fusion of the operculum and widening of the attachment area of the levator scapulae on the suprascapular cartilage, and some members of both families have lost the operculum.

The Salamandridae have lost columella and stilus as adult structures, but extend the attachment of levator scapulae ventrally by a division resulting in attachment to the scapulocoracoid, probably as an adaptation for better reception and transmission of sound vibrations in terrestrial environments.

The Plethodontidae differ strikingly in otic structure from the other families in having an operculum present in the larval stage and fused to columella, and in utilization of part of the cucullaris major as an “opercularis” muscle. These changes are probably the result of changes in orientation of the fenestra vestibuli. In plethodontids with aquatic larval stages the columella is retained as a sound‐transmitting element, but in many specialized forms it is reduced or absent.

Close correlation of otic structures with ecology limits their use as evolutionary indicators in salamanders. However, the general pattern of otic structures in salamanders, and the magnitude of differences in this region seen in plethodontids, indicates that the latter are probably not derived from the salamandrids, but from a primitive salamander stock.
Histochemistry of the “sexual segment” granules of the male rattlesnake kidney
Authors: Burtner H. J. , Floyd A. D. , Longley J. B.
Published: February 2005

The histochemistry of the “sexual segment” granules of the kidney of male diamondback rattlesnakes has been studied to define the nature of these andro‐genically responsive granules. The kidneys were variously fixed and sections stained with a number of acid dyes, as well as by a variety of carbohydrate, lipid, and protein histochemical methods. The results indicate that “sexual segment” granules bind acid dyes strongly, contain some lipids and neutral glyco‐ or mucoproteins, much tyrosine and lysine, and some tryptophan and cysteine. A resemblance, concluded to be superficial, is noted between the histochemical properties of zymogen granules and the predominantly proteinaceous “sexual segment” granules.
The development of the skull of Psammophis sibilans. I. The development of the chondrocranium
Authors: Kamal A. M. , Hammouda H. G.
Published: February 2005

The development of the chondrocranium of the Egyptian snake, Psammophis sibilans has been thoroughly studied in six developmental stages. The neurocranium and viscerocranium develop at the same time. In early stages the mesocephalic flexure is well represented, but later it is gradually reduced. The notochord is completely embedded inside the parachordal plate in the early and moderate stages, and the paired origin of the plate is not observed. From the very beginning the quadrate cartilage is in close contact with Meckel's cartilage. In early stages the two cartilages lie nearly at the same straight line, and throughout development the quadrate rotates freely until the angle between it and Meckel's cartilage becomes nearly a right one. It was impossible to find a stage at which the auditory capsules and their cochlear portions were separate from the parachordal plate. There is no interorbital septum and the platytrabic character of the chondrocranium is preserved. The basicranial fenestra, fenestrae X and the fenestra ovalis are formed by the resorption of pre‐existing cartilage. The planum antorbitale has no separate center of chondrification. The rudiment of a simplified type of concha nasalis is formed in the last stage. The lamina transversalis anterior is formed of two separate portions. The tectum synoticum is of purely otic origin.
The hypophysis and hypothalamo‐hypophysial system in the chimaeroid fish Hydrolagus colliei (Lay and Bennett) with a note on their vascularization
Authors: Sathyanesan A. G.
Published: February 2005

The pituitary of Hydrolagus is divided into four parts: the rostral pars distalis, the proximal pars distalis, neurointermediate lobe and an oral or pharyngeal component the Rachendachhypophyse. The Rachendachhypophyse may be comparable to the ventral lobe of elasmobranchs, in their position, histology and post‐ embryonic structure. A well defined hypothalamo‐ hypophysial neurosecretory system demonstrable with aldehyde fuchsin is present. The nucleus lateralis tuberis is long and seems to extend from the posterior region of the optic chiasma to the median eminence. The nucleus preopticus is situated anterodorsal to the optic chiasma. The bulk of the neurosecretory axons enter the neurointermediate lobe and have perivascular endings. At least some axons seem to terminate in median eminence, and this region is intimately connected with the pars distalis by a network of capillaries, suggesting the presence of a hypothalamo‐ hypophysial portal system. The presence of median eminence and hypothalamo‐ hypophysial portal system in elasmobranchs, and its apparent occurrence in Hydrolagus, seem to necessitate modification of earlier views concerning the phylogenetic derivation of the tetrapod neurohypophysis.
Hypothalamo‐neurohypophysial system in the normal and hypophysectomized teleost Porichthys notatus girard and its response to continuous light
Authors: Sathyanesan A. G.
Published: February 2005

The teleost Porichthys notatus has a long infundibular stalk measuring about 3 to 5 mm or more in the adult. The infundibular recess extends into the stalk in the form of a long infundibular funnel. The hypothalamo‐hypophysial system is typical of the teleosts. In the hypophysectomized fish where there was no regeneration or reorganiation of the infundibular stalk, aldehyde fuchsin‐positive substance progressively increased in quantity in the cell bodies of the preoptic nucleus. When these specimens were subjected to continuous light for 15 days, the staining intensity of the cells of the preoptic nucleus diminished, but greater accumulation of AF‐positive substance was noticed along the axonal pathway and in the infundibulum. This suggests that light might act as an activating agent causing the dispersal of the accumulated neurosecretory material from the cells along their axons.
The blood vessels of the regenerating limb of the adult newt, Triturus
Authors: Peadon Annie M. , Singer Marcus
Published: February 2005

The vessels of the forelimb stump and regenerate were perfused with Prussian blue and studied as whole mounts and in histological sections to reveal the condition and disposition of the blood vessels in various stages of forelimb regeneration in the adult newt, Triturus viridescens. The development of the vessels in the regenerate seemed to be comparable in all its essential features to that which has been described for the normal developing limb in urodele, chick and pig embryos.

The first signs of regeneration of the vessels are seen during wound healing when fine sprouts appear from the old vessels near the amputation wound. These grow and anastomose, but are limited to the transition region between old and new tissues and avoid the growing blastema during the early stages of regeneration. As the regenerate enlarges into a conical structure vessels invade the proximal part of the growth and avoid the distal regions. It is only during the stages of histogenesis and morphogenesis that vessels grow into more distal regions. The regions of most active enlargement of the early or later regenerate are those most poorly vascularized. These results are discussed against the background of the activity of certain enzymes during regeneration. In the advanced regenerate, preferential channels are consolidated until in the palette and digital stages the pattern of the blood vessels resembles that of the normal limb.
Some histochemical observations on the effects of chorioallantoic grafts on the spleen, bursa, and peripheral blood of chicken embryos
Authors: Fennell Richard A.
Published: February 2005

Hatching eggs from inbred lines of chickens (inbreeding coefficient exceeds 95%) which show various degrees of resistance and susceptibility to Rous sarcoma, were used for experimentation. Adult tissues were grafted onto the chorioallantois on the tenth day of incubation and tissues of host and control embryos were harvested on the twentieth day of incubation. Enzymes were localized in tissues by histochemical procedures.

Small pieces of tissue (thymus or bursa), when grafted onto the chorioallantois, increased the size of the spleen in host embryos although splenomegaly did not invariably occur. Two types of reactions were observed in the spleen, i.e., enlarged spleens with cysts or enlarged spleens which from a morphological point of view were normal. Grafts of either thymus or bursa decreased the size of the host embryo's bursa or were without effect. When weight of the bursa of host embryos was significantly less than that of control embryos on the twentieth day of incubation, this size relationship persisted in chicks four weeks post hatching.

Intensity of dehydrogenase and acid phosphatase reactions in cysts of enlarged spleens and in the multinucleated giant cells investing them suggests that they consist of groups of degenerating cells. Intensity of enzyme reaction indicates that enlarged spleens of host embryos in which cysts were absent were normal. Enzyme reactions in the bursae of experimental embryos were more intense than those identified in the same tissues of control embryos. Catabolic reactions were the predominant type in grafts ten days subsequent to implantation. Grafts increased the number of erythrocytes in the peripheral blood of host embryos.
The diencephalon of the primitive bony fish Polypterus in the light of the problem of homology
Authors: Nieuwenhuys Rudolf , Bodenheimer Thomas S.
Published: February 2005

The diencephalon of Polypterus can be divided into an epithalamus, thalamus, and hypothalamus. The habenulae, the nervous parts of the epithalamus, are comparable to their homologues in other lower vertebrates with respect to sulcal boundaries, cellular structure, and fiber connections. The thalamus of Polypterus is not divisible into a pars dorsalis and pars ventralis by the sulcus medius; rather this sulcus is in the middle of a uniform, laminated cytoarchitectonic field. In this respect Polypterus differs from other species in whom the sulcus medius divides the thalamus into dorsal and ventral parts. There are six migrated nuclei in the thalamus of Polypterus. There is only one circumscribed projection into the thalamus, i.e., the optic tract, but there are numerous diffuse fibers terminating in this region of the brain. The hypothalamus, except for a partially migrated nucleus, has retained the periventricular arrangement of cells. It has large fiber connections with the forebrain and brainstem.

The literature on the diencephalon of lower forms has been reviewed with special emphasis on the question of how homologies are established in this brainpart. It appeared that three different criteria, either singly or in combination, have been employed as a clue to identification of structures in the diencephalon. These are, (1) ventricular grooves, (2) nuclear boundaries, and (3) fiber connections. In order to test the practical validity of these criteria the diencephalon of Polypterus was compared to that of five related species, i.e., the actinopterygians Acipenser and Polyodon, the dipnoans Protopterus and Neoceratodus, and the crossopterygian Latimeria. In addition three amphibians, Necturus, Ambystoma and Rana, were involved in our comparative considerations. It was concluded that, within the confines of the diencephalon of the species mentioned, cytoarchitectural differences form the most valid criterion for establishing homologies. The drawback and restrictions connected with the use of ventricular sulci and fiber connections, as a clue to identification have been evaluated and discussed.
Some cytologic characteristics of the hemocytes of Limulus during clotting
Authors: Dumont James N. , Anderson Everett , Winner Gillian
Published: February 2005

The hemolymph of the horseshoe crab, Limulus (Xiphosura) polyphemus, contains a single cell type. The hemocytes are ovoid and contain many refractile granules. One‐half to one minute after the onset of clotting the hemocytes swell and a hyaline cytoplasmic ring, essentially devoid of granules, appears about their circumference. During this time the granules disperse and the nucleus becomes visible. Three to five minutes following the initiation of clotting, the cell extends long pseudopodial processes. Phase contrast time‐lapse cinematography reveals that the cells are extremely motile during this phase. Concomitant with these changes, many of the granules lose their refractility and one by one disappear from the cytoplasm leaving what appears to be a vacuole.

Electron micrographs of native (un‐clotted) hemocytes and of clots fixed in glutaraldehyde and post‐fixed in osmium reveal that the membrane‐bounded granules of native cells are very dense and homogeneous with no evidence of an internal structure. One‐half to one minute after clotting, however, they become less dense and 250 Å microtubules spaced at ca. 500 Å intervals appear parallel to the long axis of the granule. Further degradation of the granule ensues and involves (a) change to a spherical shape, and (b) further decrease in density and better resolution of the microtubules. The microtubular component subsequently disintegrates leaving a membrane‐bounded granule containing particulate material. Finally, the membrane of the granule fuses with the plasma membrane and the components of the granule are dispersed in the plasma where they presumably contribute to the formation of the gelatinous clot.
The development of the musculature of the hindlimb in the frog, Rana pipiens
Authors: Dunlap Donald G.
Published: February 2005

The major features of the morphogenesis of the muscles of the hindlimb, exclusive of the foot, are described and illustrated for the frog, Rana pipiens The description is carried through the stage XII larva, in which stage most of the muscles of the adult limb are present in essentially the definitive condition. As is true of other vertebrates which have been studied, the muscles of the hindlimb develop from two major premuscular masses. One of these lies along the dorsolateral margin of the limb and the other along the ventro‐medial margin. Each of the two masses is subsequently divided into smaller and smaller subdivisions as the different muscle groups and the individual muscles are differentiated. In general, the more proximally located muscles differentiate before those which are located more distally and those of the dorso‐lateral mass before those of the ventro‐medial mass.

The following muscles of the thigh, shank and tarsus develop from the dorsolateral mass: ileo‐fibularis, glutaeus magnus, cruralis, ileo‐femoralis, iliacus externus, iliacus internus, tensor fasciae latae, pectineus, adductor longus, peroneus, tibialis anticus brevis, tibialis anticus longus, extensor cruris brevis, tarsalis anticus, extensor digitorum communis longus and abductor brevis dorsalis. The following develop from the ventro‐medial mass: compressor cloacae, circumflexor arteriae, pyriformis, semimembranosus, gemellus, gracilis major, gracilis minor, semitendinosus, adductor magnus, obturator internus, obturator externus, quadratus femoris, sartorius, plantaris longus, tibialis posticus, tarsalis posticus, plantaris profundus, intertarsalis and flexor digitorum brevis superficialis.
The fine structure of blood cells in the ascidian Perophora viridis
Authors: Overton Jane
Published: February 2005

The fine structure of each of the blood cell types of Perophora viridis has been characterized and strong evidence for localization of vanadium in two of these types is given.

There are eight cell types; phagocytes which may contain completely engulfed cells, lymphocytes with a prominant nucleolus and scanty cytoplasm packed with clustered ribosomes, and six other cell types each with distinctive granules. Morula cells contain a central nucleus and cytoplasm filled by wedged bodies, about five of which are seen in section. These bodies contain regularly spaced electron dense foci. Green cells have the same organization but contain bodies which are electron dense throughout. Granular amoebocytes contain many smaller lightly staining oval bodies and much glycogen. Another cell type (probably orange cells of light microscopy) contains numerous granular rounded bodies. Compartment cells have vacuoles containing electron dense particles and signet ring cells have usually one large vacuole which is electron dense lined and may contain electron dense particles. Developmental stages of these cell types show involvement of endoplasmic reticulum and Golgi bodies in granule formation.

After glutaraldehyde fixation alone the only extremely electron dense components are particles in the compartment cells and signet ring cells implicating these as sites of vanadium localization, although not excluding other cell types.
The effect of molting upon the vibration receptor of the spider (Achaearanea tepidariorum)
Authors: Walcott Charles , Salpeter Miriam M.
Published: February 2005

The physiology and fine structure of the vibration receptor of the spider (Achaearanea tepidariorum) was studied throughout the process of molting. The physiological studies showed that there is no dramatic change in the receptor's vibration sensitivity as the time of ecdysis approaches. Only a gradual loss of sensitivity can be detected on a statistical basis using large numbers of spiders. The fine structural studies suggest that the connection between the sensory neurone and the receptor within the old cuticle remains intact up to the time that the cuticle is shed.
Embryonic development of the ciliary arteries of the rabbit from inception through the emergence of the circulus arteriosus iridis
Authors: Strong Leon H.
Published: February 2005

Since the rabbit's eye more nearly resembles the human eye than any other mammal used in experimental investigations, a detailed study of its ciliary arteries has been made. A closely timed series of embryos injected through the living umbilical vein and rendered transparent show, in thick sections, silhouetted vessels in perspective. Heretofore the ciliary arteries have been studied from their first identification until they have reached the primitive choriocapillaris, but no farther. This study shows their complete history including their relation to the circulus arteriosus iridis major and to the pupillary membrane. Our special concern has been ferreting out the mode of migration of the components of the definitive arteries. New findings include: (1) an arteriovenous plexus which mediates the transference from vessels anastomotic with it to other such vessels; (2) functionally different segments of the primitive ciliary arteries; (3) different arterial and venous plexuses which play roles in embryonic development; (4) discovery of the realignment of the choriocapillaris into vertical vessel meshes with transverse anastomoses between them, each of which have different fates; (5) the mode of development of the circulus arteriosus iridis major; (6) a crown of venous vessels looping around the iris margin; and (7) a special arterial supply for the ciliary processes.
Number of nucleoli in various cell types of the mouse
Authors: Shea J. R. , Leblond C. P.
Published: February 2005

The nucleoli of cells of the adult mouse were examined by staining with toluidine blue after removal of deoxyribonucleic acid from tissue sections by deoxyribonuclease treatment.

The nuclei of each cell type examined contained one or more nucleoli. This was observed even in lymphocytes and neuroglia, although these cells have occasionally been described as anucleolated. In mature spermatids and spermatozoa, however, it was not possible to detect a nucleolus.

The distribution of the number of nucleoli in many diploid cells exhibited a mode of two or three nucleoli per nucleus, and a range from 1 to 6 nucleoli.

In presumedly diploid hepatic nuclei, the maximum number of nucleoli was six; but in presumedly tetraploid hepatic nuclei, it was 11. Thus, nearly twice as many nucleoli are present when the chromosome number is doubled. In view of this observation, it is suggested that six nucleolar organizers are present in the diploid chromosomal complement of the mouse. However, through failure of some nucleolar organizers or more probably through fusion of nucleoli, the number of these organelles in most nuclei is less than six.
Electron microscope studies on the oocyte of the fresh‐water mussel (Anodonta), with special reference to the stalk and mechanism of yolk deposition
Authors: Beams H. W. , Sekhon Sant S.
Published: February 2005

An interesting relationship exists between the ovary and the developing oocyte in the fresh‐water mussel. As the oocytes grow, they elongate and bulge into the ovarian cavity. In the early stages, the nucleus migrates from the attached region (“foot”) to the distal region of the cell. With continued growth and maturation the connection between the proximal “foot” and distal nucleated portion becomes reduced to a narrow stalk. Microtubules appear in the young oocytes as they start to elongate and become packed in the stalks of older oocytes. It is suggested that the microtubules function as supporting structures and possibly also as channels for the transfer of materials from one portion of the oocyte to the other. The fine structure of the oocyte reveals evidence that the developing yolk bodies or spheres are formed, in part at least, by the incorporation of many smaller “precursor yolk vesicles.” These appear in the region of the Golgi complex and are presumed to be derived from the Golgi saccules. The oocyte contains an unusually well developed endoplasmic reticulum whose cisternae are filled with a rather conspicuous material.
A histological and ultrastructural study of germinal differentiation of interstitial cells arising from gland cells in Hydra viridis
Authors: Burnett Allison L. , Davis Lowell E. , Ruffing Faith E.
Published: February 2005

Gland cells of the gastrodermis of Hydra when isolated from the epidermis are capable of dedifferentiating into interstitial cells. Under proper environmental conditions these interstitial cells are capable of undergoing meiotic divisions and forming normal gametes. This dedifferentiation and redifferentiation sequence has been studied at the level of the light and electron microscope. It is concluded that in Hydra there is no specific germinal cell line determined during embryogeny, and that a somatic cell under proper environmental conditions can be induced to undergo meiosis.
The structure and function of the gill tufts in larval Amphipterygidae (Odonata: Zygoptera)
Authors: Watson J. A. L.
Published: February 2005

Larvae of the subfamily Amphipteryginae (Odonata) bear a tuft of tracheal gills on either side of the anus. The two tufts are derived from the laminae sub‐anales, and are protected by the non‐respiratory epiproct and paraprocts, and by plates derived from the cerci, lamina supra‐analis or the lamina sub‐analis itself. Each is approximately 1 mm long in mature larvae and comprises a series of repeatedly branching filaments, the terminal twigs of which are 5 to 10 μ in diameter. The total surface area of the tufts is approximately 5.0 mm2 in mature larvae of Devadatta, and more in the larvae of Pentaphlebia and Rimanella. Each tuft is connected by a large trachea to the longitudinal tracheal trunk. This large trachea divides many times, eventually forming a dense palisade of tracheoles in the epidermis of the filaments, immediately beneath the thin investing cuticle.
A cytological study of a chonotrichous ciliate protozoan, Lobochona prorates, from the gribble
Authors: Matsudo Hitoshi
Published: February 2005

The Ciliophora are unique in that they are heterokaryote. In certain ciliates, namely the Chlamydodontidae and Dysteriidae of the Order Holotrichida and Order Chonotrichida, the macronucleus has a chromophilic portion and a chromophobic portion. The similarities in structure and behavior of the macronucleus of Lobochona prorates to that of some lower holotrichs as well as the genesis of the ciliary mechanism suggest the close affinities of the Order Chonotrichida to the lower holotrichs — the cyrtophorine gymnostomes.

Budding, a somewhat modified binary fission preserving the fundamental structure of the parent individual, appears to be an adaption to the sessile life of the Chonotrichida. Throughout the order the process is basically similar, but there are noticeable differences from genus to genus. There appear to be two distinct patterns of budding in the Chonotrichida: (1) the parent retains its fundamental structure, and (2) the parental cytosome diminishes. Both patterns may produce one or more (multiple) buds. Diminutive budding appears to be a mechanism of these sessile organisms which enables them to abandon the exuvium of the crustacean host and to reinfest the original host or a new host.

Sexual reproduction is by conjugation. In L. prorates it occurs between adjacent individuals on the same pleopod of Limnoria tripunctata and not between a stationary individual and a “swarming” larva.
A morphological study of Luciocephalus pulcher, with notes on gular elements in other recent teleosts
Authors: Liem Karel F.
Published: February 2005

The monotypic perciform suborder Luciocephaloidei possesses the following, previously unknown, salient morphological characters: a third joint, the nasopalatopterygoid, between neurocranium and suspensorium; a toothless and dorsally exposed prevomer; no pharyngeal processes on either parasphenoid or basioccipital; a tympanum‐covered foramen exoccipitale in the saccular bulla as a hearing organ; a gular ossification; a craniovertebral joint with small exoccipital condyles widely separated from the basioccipital condyle; and a large physoclystic swimbladder with a notable caudal extension. The seemingly functionless gular‐like mental ossification is considered a paleomorphic structure with a neogenetic development. Attenuation in longitudinal growth is evident in the derivatives and dermal additions of the mandibular arch and nasal capsule while other regions of the head have remained independent. The primary adaptive significance of the attenuation in the growth of the entire preorbital region is the accomodation of oral incubation. Secondarily the elongate jaws increase both the speed and grasping range of the bite in prey catching. The degree of jaw protrusion depends mainly on the length of the maxillary. The exaggerated length of the ascending processes of the premaxillaries may be the result of a positive differential growth rate within one growth field. The meaning of the preponderance of parallel‐fibered cranial muscles is discussed in respect to holding functions, greatest possible excursion of the insertion with minimum loss of force, and muscle fiber length. Based on the overall morphology, the monotypic suborder Luciocephaloidei is retained.
Comparative responsiveness of supracaudal and other sebaceous glands in male and female guinea pigs to hormones
Authors: Martan Jan , Price Dorothy
Published: February 2005

Different types of sebaceous glands in guinea pigs were chosen to study their comparative responsiveness to steroid hormones. Glands selected were (1) Sebaceous glands associated with rudimentary hair in the supracaudal gland; (2) Free sebaceous glands of the nipple; (3) Sebaceous glands associated with the hair. The results showed distinct differences in sensitivity among these different sebaceous glands and according to the sex of the experimental animal. The most responsive of the glands in males was the supracaudal gland; in the female the most responsive glands were the sebaceous glands of the nipple. Sebaceous glands associated with normal hair were relatively insensitive to changes in hormonal level. In all cases testosterone propionate was more potent in stimulating any of the sebaceous glands than progesterone. After gonadectomy, various sebaceous glands showed unequal states of depletion due to the different rates of differentiation and disintegration of their cells into sebum.
Observations on the cervix uteri of the squirrel monkey
Authors: Colborn Gene L. , Bo Walter J. , Lang C. Max
Published: February 2005

The squirrel monkey uterine cervix was studied macroscopically and microscopically in intact and ovariectomized monkeys. The effect in ovariectomized monkeys of estradiol dipropionate or progesterone of both given after estrogen priming was studied by PAS staining.

The lower portion of the cervix was dilated to form a vestibule into which projected fibromuscular colliculi which arose from the isthmic end of the cervix. The stratified squamous epithelium of the vagina was continuous through the external os with a similar epithelium lining the vestibule and covering the external surfaces of the colliculi. The transitional zone between the stratified epithelium and columnar cells was variable. The colliculi were covered internally with mucosal folds of columnar epithelium continuous with those of the endocervical canal.

Glycogen concentration in the smooth muscle did not fluctuate markedly, irrespective of the hormones used. Glycogen granules were more numerous in the stratified squamous epithelium. Malt‐diastase‐resistant material appeared to be more abundant in the columnar epithelium and glandular lumina when the monkeys received both hormones than when they received solely estrogen or progesterone.
The tectorial membrane of the lizard ear: Types of structure
Authors: Wever Ernest Glen
Published: February 2005

This study is concerned with the forms of the tectorial membrane in the lizard ear and its manner of attachment to the ciliary tufts of the hair cells. These structures and their variations were observed in 20 species representing eight families of lizards.

Three forms of tectorial membrane were found, a continuous form that extends throughout the length of the auditory papilla, an abbreviated form that reaches the papilla only in one region, and a dendritic form that is particularly narrow at first and then branches extensively to supply all the hair cells.

Occasionally the lower edge of the tectorial membrane makes direct connections with the hair tufts. More often there are special connecting structures between the membrane and the hair tufts. Seven types of these structures were identified, as follows: (1) simple fibers, (2) open network, (3) heavy network, (4) fiber plate, (5) finger processes, (6) sallets, and (7) remote connections. These types of tectorial connections are described and illustrated.
The tectorial membrane of the lizard ear: Species variations
Authors: Wever Ernest Glen
Published: February 2005

The forms of the tectorial membrane and its connections to the ciliary tufts of the hair cells have been studied in detail in 18 species of lizards and, less thoroughly, in three others. This group, which represents eight lizard families, exhibits three forms of tectorial membrane: a complete form that connects to all parts of the auditory papilla, an abbreviated form that makes this connection only in one limited region of the papilla, and a dendritic form in which the distal portion of the membrane subdivides into strands reaching all the hair cells.

Sometimes the tectorial membrane connects directly with the tufts of the hair cells, but more often it makes this connection through intermediary structures. Seven types of such intermediary structures have been identified (if we include the sallet, which is not “intermediate” in a strict sense).

Detailed descriptions are given of the various forms of tectorial membrane structures and their variations along the auditory papilla in 12 lizard species. The description for Iguana iguana is offered as representative of the iguanid pattern found in ten members of this family.

Consideration is given to the functioning of the tectorial membrane, and also of the sallet, in the process of hair‐cell stimulation.
Functional morphology of the caudal region of certain clupeiform and perciform fishes with reference to the taxonomy
Authors: Nag Asish C.
Published: February 2005

The caudal anatomy (caudal skeleton, musculature, vascularization, innervation, and urohypophysis) and swimming behavior of three clupeiform and three perciform fishes: Elops hawaiensis (Cupeiformes: Elopidae), Oncorhynchus nerka (Cupeiformes: Salmonidae), Chanos chanos (Clupeiformes: Chanidae), Kuhlia sandvicensis (Perciformes: Kuhlidae), Apogon menesemus (Perciformes: Apogonidae), and Gnathanodon speciousus (Perciformes: Carangidae), were studdied. The taxonomic significance of caudal structures was determined and evaluated by detailed examination of differences in caudal anatomy. An interpretation of functional significance of these differences was attempted by relating them to observed differences in swimming behavior. The swimming behavior was studied by the observation of swimming activities of fish while resting or cruising and while feeding in the aquarium, and by an analysis of each frame of an 8 mm movie film of swimming activities.

There are certain consistent and basic differences between all three species of the order Clupeiformes and all three species of the order Perciformes in respect to caudal structures. Although certain caudal structures show overlapping in number and/or complexity of arrangement, they seem to indicate more complex structural organization in Clupeiformes than Perciformes. The differences confirm the conclusion of others that the order Clupeiformes is more “primitive” than the order Perciformes.

With respect to caudal structures of the three clupeiform species studied, E. hawaiensis is the most “primitive” and, of the three perciform species studied, K. sandvicensis is the most “primitive.”

Caudal structural variations from one species to another are related to the mode of adaptation to swimming as well as to the evolutionary status of the species.
The development of the female Drosophila reproductive system
Authors: King Robert C. , Aggarwal Surinder K. , Aggarwal Urmila
Published: February 2005

Light and electron microscopical studies allow a descriptive account to be given of the preadult development of the ovary of Drosophila melanogaster. The lineage of the cell groups which contribute to the tissues of the adult ovary has been determined. The earliest morphologically detectable event in the differeentiation of each ovariole is the formation during the larval period of its terminal filament. Oogonia play no role in the induction of terminal filaments. The developmental events which transform a spherical mass of ovarian cells into a collection of multicellular cylinders is described. The importance in morphogenesis of acellular membranes secreted at the interface separting cells of different prospective significances is stressed. Such membranes may serve to regulate the future migration of cell populations or as sites of attachment for monolayers of cells which later fuse to form multinucleated muscle sheaths. The transformation of oogonia to cystoblasts coincides with and presumably depends upon the same hormonal stimulus which causes metamorphosis. The first oocytes to undergo crossing over do so between 24 and 36 hours after puparium formation.
Autoradiographic studies of uridine incorporation in peripheral nerve of the newt, Triturus
Authors: Singer Marcus , Green Marie R.
Published: February 2005

Autoradiographic studies combined with digestion tests of incorporated 3H‐uridine showed that the peripheral nerve of Triturus contains ribonucleic acid. Localization studies revealed the presence of RNA in the axon, in the myelin and Schwann sheath, and in the Schwann cell body. Similar experiments on nerve separated by transection from its neuronal cell bodies yielded the same results. They showed that RNA of the nerve can be synthesized without the intervention of the neuronal cell body. The results strongly suggest that the radioactive substance, precursor or RNA, is transported inward from the Schwann cell to be deposited in the myelin sheath and axon. The route of passage and the possible sites of origin of the RNA in the nerve are discussed. A significant role is suggested for the Schmidt‐Lantermann cleft because of its relations with the adaxonal layer of Schwann cytoplasm and with the myelin leaflets.
Symmetrical gaits of dogs in relation to body build
Authors: Hildebrand Milton
Published: February 2005

Symmetrical gaits of 37 breeds of dogs were analyzed. Usual walking and trotting gaits resemble those of other carnivores of similar size and conformation. Only certain long‐legged dogs pace – usually at the fast walk or slow run. At the moderate walk, long‐legged dogs tend to use lateral‐couplets gaits, whereas short‐legged breeds tend to use single‐foot gaits. Many dogs must turn the axis of the body slightly from the line of travel at the trot to prevent interference between fore and hind feet. The relative duration with the ground made by fore and hind feet is discussed, usual support‐sequences of the varicus gaits are presented, and the amount of variation is shown.
On the respiratory organs of Amphipnous cuchia (Ham. Buch.)
Authors: Datta Munshi J. S. , Singh B. N.
Published: February 2005

The respiratory organs of Amphipnous cuchia comprise a pair of aicsacs, vestigial gill filaments borne on second gill arch and vascular folds of the third gill arch. The volume of each air‐sac, its surface area and its reltionship with the body weight of the fish have been determined. The air‐sac is lined by a respiratory mucosa which is composed of vascular and non‐vascular areas. Each vascular area, called here the ‘respiratory islet,’ studded with hundreds of vascular rosettes, which are formed of collagenous material and supported by endothelial cells. Pilaster cells are absent. The ‘islets’ are covered over by a single layer of squamous type of epithelial cells.

The non‐vascular areas (lanes') are the stratified part of the respiratory epithelium and contain a large number of mucous glands which secrete mainly acid mucopolysaccharides.

The vascularisation of the gills have been studied by India ink injection methods. The secondary gill lamellae are absent, their place being taken up by coiled vascular loops.

A quantitative estimation of haemoglobin in blood of ‘cuchia’ and other air‐ and water‐breathing fishes have been made by colorimetric method and the results have been discussed in relation to their habit and habitats. The cranial muscles which are involved in respiration of ‘cuchia’ and the mechanics of muscle action in breathing have been described.
Later stages of regeneration in the polychaete, Nephtys
Authors: Clark Mary E.
Published: February 2005

The sequence of events in posterior regeneration of the polychaete, Nephtys, has been examined in histological preparations from the fifth day to the end of the third week after amputation, that is from the time when wound healing is complete until several new segments are differentiated. The pygidium forms and begins to differentiate prior to segmentation. The first indication of each new segment is the appearance of a large pair of segmental blood vessels which arise from the vascular complex in the gut wall. Associated with these are fibroblasts, the anlagen of the new septum. Epidermal derivatives develop subsequently, appearing first ventrolaterally, close to the regenerating nerve cord. The mitotic rate appears to be highest prior to the period of maximum segment formation. Visible cell differentation follows, and subsequent growth of segments is primarily by cell enlargement. It appears likely that the blood‐vascular system associated with the gut and the regenerating nerve cord, both of which are disproportionately large in the regenerate, are important for the initiation of new segments.
Cortical alveoli formation and vitellogenesis during oocyte differentiation in the pipefish, Syngnathus fuscus, and the Killifish, Fundulus heteroclitus
Authors: Anderson Everett
Published: February 2005

The formation of cortical alveoli and yolk has been investigated in the pipe‐fish, Syngnathus fuscus, and the killifish, Fundulus heteroclitus by techniques of light and electron microscopy. In addition to cortical alveoli and yolk components the ooplasm contains many mitochondria, numerous Golgi complexes, copious quantities of the endoplasmic reticulum of the rough variety, ribosomes and particulate glycogen. While the formation of cortical alveoli and yolk may proceed simultaneously, the cortical alveoli are the first to develop. Staining procedures indicate that cortical alveoli, like some of the yolk bodies contain a polysaccharide component and protein. It is suggested that the protein portion is made by the endoplasmic reticulum and is subsequently transferred to the Golgi complex via vesicles. Within the saccules of the Golgi complex the polysaccharide component is fabricated after which time the Golgi produce vesicles containing the products of either the cortical alveoli or yolk bodies.

The precursors used in the production of the yolk are produced by the oocyte (endogenous) and by an organ other than the ovary (exogenous). The precursors made exogenously become associated with the morphologically and physiologically specialized oolemma and are subsequently internalized by the process of micropinocytosis.
Regeneration of the completely excised gastrocnemius muscle in the frog and rat from minced muscle fragments
Authors: Carlson Bruce M.
Published: February 2005

In 85 frogs and 29 rats, the entire gastrocnemius muscle was removed. After removal of as much connective tissue as possible, about two‐thirds of the remaining muscle was finely minced with a scissors. These minced fragments were orthotopically re‐implanted, and the overlying skin was sutured. As the implanted muscle fragments degenerate, new muscle fibers appears in the regenerate. The proportion of connective tissue to muscle is usually greater than normal especially in the frog. Grossly, normal relationships are established with the cut ends of the Achilles and proximal tendons, as well as with the blood vessels and nerves. The total diameter of the regenerated muscle is almost always less than half of that seen in normal muscles. Regeneration of muscle is much more extensive in the rat than in the frog, and it occurs almost twice as rapidly. The histology of the regenerative process is described for both the frog and the rat.