bluuebunny/crossref_metadata_2025 huggingface dataset:
Organization of the teleostean nucleus rotundus
Authors: Ito Hironobu , Kishida Reiji
Published: February 2005

The nucleus rotundus of 21 species of teleosts was studied by a modified Bodian and the Golgi method to clarify the histological organization, with special reference to the cell lamination and the glomerular formation.

The common components of the nucleus in all species are as follows: a thick fiber bundle which comes from the commissura horizontalis and enters the nucleus from the dorsal surface, many small cells, large cells, glomeruli, and a surrounding fibrous capsule. The nuclei of all species studied are classified into three types mainly on the distribution of the small cells, and to a lesser degree on the location of the large cells and the glomeruli.

The first type of nucleus has small cells. large cells and glomeruli throughout its extent. In the second type of nucleus, many small cells form a peripheral cell layer, while the large cells and glomeruli are found all over the nucleus.

The third type of nucleus is clearly laminated. It is composed of four layers arranged concentrically around a central fiber net in the following order: a glomerular layer, a fibrous layer, a small‐cell layer, and a peripheral fibrous capsule. In some species, the large cells are located in the fibrous capsule, and all glomeruli contain a star‐like structure, which corresponds to the tips of the large cell dendrites.
The anatomy of the parotoid gland in Bufonidae with some histochemical findings II. Bufo alvarius
Authors: Cannon M. Samuel , Hostetler Jeptha R.
Published: February 2005

The gross and microscopic anatomy of the venom producing parotoid glands of Bufo alvarius has been studied by light and electron microscopy. Histochemical reactions for the presence of venom constituents and of components in biochemical pathways in the synthesis and release of venom were performed. The gland is composed of numerous lobules. Each lobule is an individual unit with a lumen surrounded by a double cell layer. Microvilli of the outer layer interdigitate with microvilli of the inner layer. Cells of the outer layer resemble smooth muscle cells, are rich in adenosine triphosphatase and glucose6‐phosphatase, and contain numerous pinocytotic vesicles, glycogen granules and various organelles, These organelles include “crystalloids” of what seem to be highly organized agranular reticulum. These outer layer cells probably function in some aspects of venom synthesis, active cellular transport and contraction in the discharge of the secretory product. The inner cell layer demonstrates a positive chromaffin reaction, contains steroid material, various organelles, some pinocytotic vesicles and glycogen granules, and appears devoid of a plasmalemma on its inner surface. This layer is probably involved in venom formation and release via an apocrine type of secretion.

Bufo alvarius parotoid gland shows significant morphological and histochemical differences from that of B. marinus and more nearly resembles a typical steroid producing organ.
Burrowing in frogs
Authors: Emerson Sharon B.
Published: February 2005

More than 95% of burrowing Anura dig hindfeet first into the soil, a pattern unique to frogs among terrestrial vertebrates. The postero‐laterally placed hindlimbs and associated musculature of frogs are preadaptations for hindfeet digging. One fossorial, backwards burrower, Glyphoglossus molossus (Microhylidae), has morphological modifications of the hindlimb for positioning the spade‐like metatarsal tubercle and for increasing the force of the lower leg during digging.

In contrast, in the headfirst burrower Hemisus marmoratus (Ranidae) there is extensive reorganization of the pectoral‐cranial morphology compared to that: of a non‐burrowing confamilial species. A model links the shifts in the pectoral morphology in Hemisus marmoratus to specific action patterns of headfirst: burrowing.

Finally, data on stomach contents, natural history and energy utilization of frog species are presented to demonstrate the interrelationships of distinct loco. motor patterns with specific feeding strategies.
Ultrastructure of the vasa deferentia of the mediterranean flour moth
Authors: Riemann John G. , Thorson Barbara J.
Published: February 2005

Each vas deferens of the Mediterranean flour moth, Anagasta kuehniella (Zeller), consists of a short swollen portion immediately below the testis, another swollen portion that forms a seminal vesicle, and an elongate lower portion that empties into one arm of the ductus ejaculatoris duplex. Three types of epithelial cells occur sequentially. Phagocytic cells that engulf debris from the testis form the anterior two‐thirds of the first swollen portion. Tall secretory cells form the distal third of the first swollen region and extend to the seminal vesicles. The secretory cells surround a slit‐like lumen and appear to function as a valve between the two swollen regions. Many membrane‐enclosed secretory granules are stored at the apical ends of the cells and are released into the lumen together with small amounts of the surrounding cytoplasm. The granules remain intact while they are in the male tract. A second type of secretory cell forms the walls of the seminal vesicles and the lower vasa deferentia. These cells produce secretory granules whose contents become dispersed through the semen. PTA‐chromic acid staining indicates that the seminal plasma has a high glycoprotein content. A thin muscle layer is basal to the epithelial cells. Both apyrene and eupyrene sperm undergo some development in the vasa deferentia. The epithelial cells, muscle, and stored sperm all undergo extensive changes with age.
The neck region of the spermatozoon of Discus rotundatus (Müller) (Pulmonata, Stylommatophora)
Authors: Maxwell W. L.
Published: February 2005

The neck region of the mature spermatozoon of Discus rotundatus is described. No evidence for a centriole or centriolar derivative is obtained. Nine striated coarse fibres and the two central fibres of the axoneme extend into the base of the implantation fossa. The axonemal doublet system is disrupted in the neck region. There are two fibrous accessory structures located between the central doublet and the striated coarse fibres.
Labellar taste organs of Drosophila melanogaster
Authors: Falk Raphael , Bleiser‐Avivi Naomi , Atidia Judith
Published: February 2005

There are 36 to 42 taste bristles on each half of the labellum of Drosophila melanogaster; most of them are two‐pronged with a pouch between them. Some end bluntly with a pore at the tip.

Each taste‐bristle has two lumina: one is circular, the other crescent‐like in cross section. In most bristles four dendrites of chemoreceptor neurons run along the circular lumen. In five to seven taste‐bristles only two chemoreceptor neurons are found. A mechanoreceptor neuron sends a dendrite to the base of each taste‐bristle.

The dendrites are surrounded by four concentrically‐arranged sheath cells. The inner cell secretes the cuticular sheath; cells II and III are presumably two trichogens, one secreting the bristle material around the circular lumen, the other around the crescent‐like lumen. Cell IV, especially rich in bundles of microtubules, secretes the cuticle of the socket, and corresponds to the tormogen. The neurons have the typical structure found in insect sensilla. In many sensilla one neuron is less electron‐dense than the others and may be the water‐sensor.

On the medial side of the labellum between the pseudotracheae are rows of taste pegs covered by folds. In each peg one chemoreceptor and one mechanoreceptor are found.

The number of axons in each labial nerve agrees with the total number of dendrites in all taste organs of each lobe.
Observations on the ultrastructure of developing myocardium of rat embryos
Authors: Chacko K. John
Published: February 2005

Timed pregnancies were obtained in Sprague‐Dawley rats and early ultrastructural differentiation of myocardium of embryos of 10, 11, 12, 13, and 14 days was investigated and compared with that of newborn. Ten‐day myocardium is characterized by loosely packed cells; the cytoplasm is typified by a dearth of organelles. Both thick (myosin) and thin (actin) filaments become identifiable for the first time in the 10‐day myocardium where the heart is pulsating but circulation is not established. These filaments are not visible in the embryos of 9‐day‐old myocardium. The formation of these filaments is observed to continue throughout the period covered in this investigation. Concomitant with the appearance of the myofilaments is the synthesis of Z band material. By the eleventh day of gestation and during the subsequent days there is a rapid proliferation and differentiation of most of the organelles. The myofilaments become organized into fully formed striated fibrils. Intercalated discs appear as. small wavy lines on the eleventh day and become plicated in later stages and serve as cell boundaries and points of attachment for myofilaments and fibrils. There is a perceptible change in the number and morphology of mitochondria from the tenth to eleventh day and later stages of development when the heart becomes functional. Similarly, there is a rapid proliferation and differentiation of granular endoplasmic reticulum and Golgi bodies. Large quantities of free ribosomes are dispersed in the cytoplasm of 10‐day myocardium; however, in later stages there is a progressive reduction in the distribution of these particles. An intimate association of ribosomes and polysomes with the developing myofibrils is discernible. The T ‐system and sarcoplasmic reticulum begin to appear in II‐day myocardium. The embryonic myocardium displays intense mitotic activity throughout its development and a unique feature of embryonic myocardial cells is the simultaneous occurrence of myofilament synthesis and mitotic activity within the same cells.
Integumental organs of unknown function on chelipeds of deep‐sea crabs, genus Hypsophrys
Authors: Williams Austin B.
Published: February 2005

Homolid crabs (Hypsophrys) from water deeper than 700 m in the Straits of Florida and Arabian Sea have smooth darkened oval spots contrasting with the surrounding roughened integument on inner and outer surfaces of each pincer at the base of the fixed finger. Cuticle is thinner over these spots than over surrounaing tissues. Beneath each spot is an organ composed of two markedly contrasting layers of tissue: (1) an outer, densely staining layer of tightly packed tubules, relatively straight and perpendicular to the overlying surface proximally but progressively convoluted and narrowed distally, finally ending blindly in association with the overlying thinned cuticle; (2) an inner layer of relatively large, eosinophilic, irregular cells with dark nuclei also trending at a right angle to the integument and bulging into the hemal sinus of the hand but separated from it by an epidermal lining. Droplets secreted from the inner layer apparently move into and along the tubules. Similar organs are known in no other crabs. The function is unknown but the structure suggests that they may be photophores.
Postembryonic ontogeny and functional anatomy of the ligamentum mandibulo‐hyoideum and the ligamentum interoperculo‐mandibulare, with notes on the opercular bones and some other cranial elements in Salmo gairdneri Richardson, 1836 (Teleostei: Salmonidae)
Authors: Verraes Walter
Published: February 2005

This study deals with the development of the opercular bones the ligamentum mandibulo‐hyoideum, the ligamentum interoperculo‐mandibulare and with some aspects of the development of the ceratohyale and the cartilago meckeli during postembryonic ontogeny of Salmo gairdneri (rainbow trout). It is stated that the ligamentum mandibulo‐hyoideum is present from hatching onward, while the development of the ligamentum interoperculo‐mandibulare appears during the period of active feeding. Some functional reasons are proposed to explain these facts. It is further suggested that the opercular bones develop under influence of the opercular muscles.
Comparative fine structural studies of planulae and primary polyps of identical age of the sea pen, Ptilosarcus gurneyl
Authors: Chia Fu‐Shiang , Crawford Bruce
Published: February 2005

Electron microscopic study of an 18‐day‐old planulae and primary polyps of the sea pen, Ptilosarcus gurneyi, reveals 14 cell types: sustentacular cell A, sustentacular cell B, nerve cell, sensory cell, cnidoblast, interstitial cell, five types of gland cell (A, B, C, D and E), amoebocyte, style cell and endodermal cell. Of these, 9 are found in the planula, 12 in polyps and 7 are common to both stages. The fine structure of all cell types is described.

Since the planulae and polyps in this study were identical in age of development, the gaining and losing of certain types of cells in the polyp are attributed to changes associated with settlement and metamorphosis. Modifications of the seven common cell types during metamorphosis can also be attributed to the change of life style from pelagic to benthic.
Initiation of the actinotrichial development in the early fin bud of the fish, Salmo
Authors: Géraudie Jacqueline
Published: February 2005

Ultrastructural analysis of initial development of actinotrichia, the skeleton anlage of the pelvic fin buds, was performed on the rainbow trout, Salmo gairdneri. It shows that the first actinotrichial rudiments appear in the subepidermal space of the pseudoapical cap. No mesenchymal cell bodies or their filopods are present. Hyaloplasmic protrusions of the basal epidermal cells are seen in the subepidermal space, limited by a dermoepidermal boundary reduced to a discontinuous thin adepidermal lamina without a collagenous layer. These morphological data suggest that the epidermal pseudoapical cap probably initiates the development of actinotrichia. Later, mesenchymal cells invade the subepidermal space and are probably involved in the further growth of actinotrichia.
Histological and histochemical studies on the nervous influence on minced muscle regeneration of triceps surae of the rat,
Authors: Mong Franz S. F.
Published: February 2005

The degree of minced rat muscle regeneration in the absence of nerve fibers was compared with that of normal regenerates between one and 270 days postoperatively. Up to around 30 days, the number of muscle fibers and their morphology were comparable in both normal innervated and denervated regenerates; both showed clear cross striations and peripherally located nuclei. Histochemically, SDH and myofibrillar ATPase (pH = 9.4) reactions were positive, but there were no typical signs of fiber types in either case of regeneration. The only consistent difference in the early period was the smaller fiber cross sectional areas in denervated regenerates than in innervated ones. Starting about 40 days, the muscle fibers in innervated regenerates became differented into different fiber types (fast‐twitch‐oxidative‐glycolytic, FOG., fast‐twitch‐glycolytic, FG., slow‐twitch‐oxidative, SO.) but there were no such activities in denervated regenerates, although their SDH and myofibrillar ATPase reactions remained positive for a long time. Degenerating muscle fibers could no longer be identified in innervated regenerates. In the denervated regenerates, however, muscle fibers underwent atrophic or degenerative changes and were replaced by connective tissue. The complete disappearance of muscle fibers varied with individual regenerates. In some cases, it occurred about 90 days and in others, traces of muscle fibers could still be seen as late as 150 days postoperatively. Thus, nerves seem to be important primarily in the late phase of regeneration; namely, differentiation of fiber types and maintenance of the structural integrity of muscle fibers.
Comparative study of the stomatogastric system of several decapod crustacea. I. Skeleton
Authors: Meiss Dennis E. , Norman Richard S.
Published: February 2005

The skeletal structure of the stomachs of several decapod Crustacea is described in detail. The general organization of the ossicles is similar for all species and the homologies of the elements can be recognized despite large variations from group to group. The Reptantia are characterized by a complex ossicle organization while the Natantia, on the other hand, are characterized by a simple organization. The various types of ossicle organization found in the decapod stomach can be arranged in a series ranging from simple to complex. The Brachyura have the most complex ossicle system and the Penaeidea the most simplified. This graded series of complexity closely follows the evolution of the Decapoda.
Some correlates of cranial and cervical morphology with predatory modes in snakes
Authors: Ruben John A.
Published: February 2005

Dissection of the cervical and basicranial regions in three species of snakes indicates that compared to Crotalus viridis and Lichanura roseofusca, Masticophis flagellum possesses relatively high numbers of compound axial muscle insertions on the atlas‐axis and vertebrae numbers 3‐5. It is suggested that the condition in Masticophis facilitates its vertical‐neck‐horizontal‐head foraging posture and has allowed axial muscles inserting on the dorsocaudal braincase in this snake to generate vertical and lateral head movements more effectively.
Embryogenesis of Xyleborus ferrugineus (Fabr.) (Coleoptera, Scolytidae). I. External morphogenesis of male and female embryos
Authors: Beeman Sylvia L. , Norris Dale M.
Published: February 2005

A description of the external morphogenesis of male and female embryos of X. ferrugineus, derived from in vivo observation, is presented here. The embryogenesis of this beetle is typical of the Coleoptera, and is also similar in most respects to the generalized insect plan. Observed unusual aspects of X ferrugineus embryogenesis include the precocious formation of primordial g/rm cells and their temporary exclusion from the somatic blastoderm, the precocious in situ delineation of gnathal metameres, the closing of the gastral groove beginning at both ends and proceeding toward its middle, the formation of several paired lateral amnio‐serosal folds, the formation of cellular processes between the amnion and serosa, and the absorption of the thoracic limbs to produce an apodous larva. The embryonic developmental picture provided here, and the previously established means of rearing X ferrugineus in controlled laboratory culture jointly provide a promising basis for the further use of this insect in developmental studies.
Comparative studies on the structure of reproductive organs of four botryllid ascidians
Authors: Mukai Hideo
Published: February 2005

Reproductive organs of four botryllid ascidians, Botryllus primigenus, Botryllus schlosseri, Botrylloides violaceus and Botrylloides leachi, were studied histologically. In every species, the egg follicle consisting of an egg and its inner and outer follicles, is attached to the follicle stalk, the vesicle being composed of a flat epithelium, which in its turn is connected to the atrial epithelium or to the brood pouch specialized from it. In B. schlosseri, the egg is ovulated into the atrial cavity and remains there held by the brood cup, of which the inner epithelium is derived from the follicle stalk and the outer one from the atrial epithelium. In B. primigenus, the brood pouch develops as a diverticulum of the atrial cavity, around the entrance of which a fold differentiates from the atrial epithelium and closes the pouch during embryogenesis. In both species of Botrylloides, the brood pouch is formed by the outgrowth of the thickened atrial epithelium into the blood space, the entrance of which is closed during embryogenesis. The discarded outer follicle completely disintegrates soon after ovulation in B. schlosseri, but part of it remains throughout embryogenesis in the blood space in B. primigenus or projecting into the interior of the brood pouch in Botrylloides. In B. primigenus, the testis, when it accompanies the egg follicle, is placed at the bottom of the brood pouch and the sperm is shed through the pouch prior to ovulation. In B. schlosseri and the Botrylloides species, the testis is located independently from the egg follicle and the sperm matures after ovulation.
Tooth replacement in the teleost fish Prionurus microlepidotus Lacépède
Authors: Wakita Minoru , Itoh Katsuhiro , Kobayashi Shigeo
Published: February 2005

Previous studies on tooth replacement in lower vertebrates have been plagued by a lack of common integrative approaches and methods, making it impossible to furnish a phylogenetic synthesis. This study is based on serial sections of the jaw of Prionurus microlepidotus. Each Toothgerm was characterized by its developmental stage and its position in the jaw. The relationship between the developmental stage of toothgerm and position in the jaw has been studied and expressed in several graphical illustrations. The following conclusions have been made: (1) The initiation of toothgerms in P. microlepidotus is governed by two Zahnreihen, which respectively initiate toothgerms on the lingual and labial side of the functioning teeth in an alternating pattern. (2) Therefore, functioning teeth in one locus are supplied by the alternate eruption of lingual and labial toothgerms. (3) Advancing of tooth replacement in each locus is independent of functioning teeth and their successors in adjacent loci. (4) The disorders of replacement patterns are caused by an alternated rate of eruption of successive toothgerms as a response to unusual shedding of the functioning teeth.
Arrangement and structure of sinus hair muscles in the big‐clawed shrew, Sorex unguiculatus
Authors: Yohro Takeshi
Published: February 2005

The arrangement and structure of sinus hair muscles in the snout of the shrew, Sorex unguiculatus, were studied by electron microscopy and serial section light microscopy. Both striated and smooth muscles are directly associated with sinus hair follicles. The striated muscle fibers originate from the base of a follicle and insert onto the superficial portion of adjoining caudally positioned follicles. Some fibers insert into the corium instead of inserting into a follicle. The fibers show a fine structure typical of red fibers. Smooth muscle cells form a network with elastic fibers beneath the corium. Some cells are directly attached to the capsule of the sinus, thus forming a type of M. arrector pili. Striated muscle fibers that appear to end in the corium are connected with the smooth muscle network through the elastic fibers which appear to function as the tendon of these two types of muscle cell.
Vascular follicle system of the sea cucumber, Stichopus moebii
Authors: Herreid Clyde F. , Defesi Charles R. , Larussa Vincent F.
Published: February 2005

Sea cucumbers, Stichopus moebii, have a unique specialization of their blood vascular system: The vascular follicle network is composed of numerous small chambers (follicles) interconnected by minute vessels. The fine structure of the follicle system was studied in detail. The follicles are composed of several layers: an external ciliated epithelium, neuromuscular layer and basement membrane, connective tissue, and a fenestrated endothelial lining. The follicle lumen is filled with coelomocytes and necrotic cells surrounding particles of iron. The follicle may function in coelomocyte production and destruction.
Ultrastructural study of the normal degeneration of the intersegmental muscles of Antheraea polyphemus and Manduca sexta (Insecta, lepidoptera) with particular reference to cellular autophagy
Authors: Beaulaton Jacques , Lockshin Richard A.
Published: February 2005

In studying ultrastructural changes in metamorphosis‐related degeneration of intersegmental muscles in Antheraea polyphemus, particular attention was directed to the mechanisms and timing of degradation of organelles and myofilaments. At emergence, the muscles are typical slowly contracting insect muscles, with a few dense body lysosomes and occasional autophagic vacuoles containing mitochondria. During the early phases of degradation the number of autophagic vacuoles, dense bodies, and lamellar bodies increases rapidly, along with an expansion of the Golgi system and the T system. Free glycogen particles and glycogenosomes are demonstrated by the PATAg test.

Between 7 and 20 hours after ecdysis the T system continues to expand, the fibers subdivide, and the contractile system is degraded. Myofibrils fragment; myofilaments are not enclosed in isolating membranes at the time of their dissolution. The destruction of individual filaments occurs rapidly, with few intermediate stages being seen, while thick filaments tend to disappear earlier than thin filaments and Z‐line material. The process is generalized and not confined to specific regions of the fiber. Autophagy destroys cell organelles in apparent synchrony with the first signs of nuclear pycnosis.

By 20 to 30 hours after emergence, the fibers are reduced to lamellae of polynucleate sarcoplasm containing no organized contractile material. The sarcoplasm is filled with autophagic vacuoles containing mitochondria, dense lamellar or residual bodies, and ribosome‐rich sarcoplasm. The number of mitochondria is drastically reduced at this time.

In the final phases of involution (40–49 hours after emergence) shedding of the residual sarcoplasm precedes the expulsion of the pycnotic nuclei into the hemocoele.

These results indicate that autophagy is responsible for the selective destruction of mitochondria, glycogen particles, ribosomes, and other organized sarcoplasmic structures. The one exception is the dissolution of the myofilaments, a process which remains undefined but which appears to be independent of lysosomal activity.
Oxytalan fibre organization in marsupial mandibular periodontal tissues
Authors: Sampson W. J. , Sims M. R.
Published: February 2005

The arrangement and distribution of oxytalan fibers in Australian marsupials has not previously been reported. Periodontal tissues of wombat, wallaby, possum, and marsupial mouse were examined to ascertain oxytalan fibre organization. Despite adaptation of the marsupial masticatory apparatus to different diets the oxytalan fibre organization in the periodontal ligament shows a basic pattern which corresponds with that reported in other animals. The oxytalan system forms a continuous meshwork of fine, branching fibres which completely invests each tooth root and connects adjacent teeth. Thick ribbon‐like apico‐occlusally orientated oxytalan fibres, thought to form by the coalescence of thinner fibres, are restricted to the periodontal ligament. The oxytalan fibres are embedded in cementum and attached to blood vessels in the periodontal ligament. Oxytalan fibres do not insert into alveolar bone. Histological evidence indicates functional remodelling of the oxytalan fibre system in continuously erupting teeth.
An electron microscopic study of early developmental stages, myogenesis, oogenesis and cnidogenesis in the anthomedusa, Podocoryne carnea M. Sars
Authors: Boelsterli Urs
Published: February 2005

This descriptive electron microscopic study of the blastogenetic medusa development of Podocoryne carnea focuses on the earliest stages of primordium formation, myogenesis, oogenesis and cnidogenesis. The events which take place at the cellular level prior to the formation of stage 1 (Frey, '68), which are characterized by ecto‐ and entodermal accumulations of undifferentiated I‐cells and the beginning of transdifferentiation of epithelial cells, have been subdivided into four distinct stages (U1‐U4). The genealogy of cells participating in medusa differentiation indicates that some cell types of the medusa are derived by transdifferentiation from the polyp's epithelial cells, while others originate by differentiation from I‐cells. The myogenesis of the subumbrellar muscle cells resembles vertebrate myocardiac differentiation in many respects.
Fine structural changes in the mandibular gland of the male spider crab, Libinia emarginata (L). Following eyestalk ablation
Authors: Hinsch Gertrude W.
Published: February 2005

Mandibular glands from destalked male spider crabs were fixed in glutaraldehyde‐paraformaldehyde, post‐fixed in 1% osmium in phosphate buffer, dehydrated in acetone and embedded in Spurr's low‐viscosity medium ('69). The glands hypertrophy and several changes occur in the subcellular cytoarchitecture following eyestalk ablation. These include loss of most of the smooth endoplasmic reticulum or its appearance as lamallae, appearance of numerous polysomes and a change in mitochondrial structure. Large vesicles with ribosomes spaced at intervals along their membranes are apparently formed by blebbing of the outer nuclear membrane and appear throughout the cytoplasm. Banded structures consisting of alternate granular and flocculent materials are found within the nucleus.
Fine structure of tarsal sensilla of Aedes aegypti (L.) (Diptera: Culicidae)
Authors: McIver Susan , Siemicki Roman
Published: February 2005

The tarsi of all three pairs of legs of both sexes of Aedes aegypti (L.) bear spine sensilla, five types of hair sensilla, which are designated A, B, C1, C2 and C3, and campaniform sensilla. Type A and B hairs, spines, and cam‐paniform sensilla are innervated by one neuron with a tubular body, a characteristic of cuticular mechanoreceptors. In particular the hairs and spines are tactile receptors and the campaniform sensilla are proprioceptors. The C1, C2, and C3 hair sensilla have the morphological features of contact chemoreceptors. Type C1 and C3 hairs are innervated by five and four neurons, respectively, which extend to the tip of the hair. Type C2 is innervated by five neurons, one of which terminates at the base of the hair in a tubular body while the remaining four extend to the tip of the hair. The role of the type C hairs in oviposition behavior, nectar feeding, and recognition of conspecific females is discussed. Presumed efferent neurosecretory fibers occur near the spine and hair sensilla.
Repair and reorganization of minced cardiac muscle in the adult newt (Notophthalmus viridescens)
Authors: Bader David , Oberpriller John O.
Published: February 2005

Studies of the response of adult mammalian and amphibian ventricle to injury have indicated the formation of a connective tissue scar in the place of the wounded or amputated muscle. It has been demonstrated that amphibian myocytes adjacent to a wound surface, unlike mammalian myocytes, have a proliferative capacity. In the present study, a minced cardiac muscle graft was placed into the adult newt ventricle in order to increase the number of myocytes near a wound surface. With such an increased number of reactive myocytes, it was thought a new wall consisting primarily of muscle might be formed. One‐sixteenth to one‐eighth of the ventricular apex was removed, minced and returned to the amputation surface of the ventricle. General histological and autoradiographic studies were conducted on two sham‐operated animals and on five experimental animals which were killed at 5, 10, 20, 30, 50 and 70 days after surgery. Major events of the repair and reorganization of minced cardiac muscle included blood clot formation followed by necrosis of the blood clot and much of the muscle graft. By ten days, an apparent coalescence of muscle fragments and continuity of ventricular and graft lumina were observed, although the graft area never formed an integrated unit with the wounded ventricular wall. The peak of mitotic activity (3.19%) and thymidine labeling (28.1%) of graft cells, including many cells which resembled cardiac myocytes, was observed at 20 days. At 30 days, the graft was observed as a continuous wall composed primarily of muscle fibers. Several 30‐, 50‐ and 70‐day grafts had rhythmic contractions. These results suggest that amphibian cardiac muscle has histogenetic and proliferative capacities not attributable to mammalian cardiac muscle.
Cyclic changes in fine structure of the epithelium lining the ovary of the viviparous teleost, Cymatogaster aggregata (Perciformes: Embiotocidae)
Authors: Gardiner David M.
Published: February 2005

The most striking morphological feature of the ovarian epithelium of Cymatogaster is the presence of intercellular dilations during much of the year. These dilations increase markedly in volume during the several months prior to ovulation and fertilization, and decrease in volume during the months of embryogenesis and gestation. The epithelium then returns to its initial, relatively undifferentiated state. The extracellular material within the dilations likely is synthesized in the cells adjacent to or within the dilations. Apparently most of this material is released into the ovarian lumen when the apicolateral margins of adjacent epithelial cells pull apart; possibly it serves as nutrient for developing embryos.

In addition to supporting embryogenesis, the ovarian epithelium also apparently is involved in sperm storage. Sperm are maintained within pockets in the ovarian epithelium for the several months between insemination and fertilization. The cells lining the sperm pocket do not develop the intercellular dilations characteristic of most of the ovarian epithelium, and sperm remain associated only with the sperm pocket cells.
Time‐lapse cinemicrographic analysis of superficial cell behavior during and prior to gastrulation in Xenopus laevis
Authors: Keller R. E.
Published: February 2005

Time‐lapse cinemicrography was used to show what changes in the number, size, shape, arrangement and what movements of apices of superficial cells occur during epiboly, extension, convergence and blastopore formation in the blastula or gastrula of Xenopus laevis. Epiboly of the animal region occurs by apical expansion of superficial cells at a nearly constant rate from the midblastula to the midgastrula stage. Egression of deep cells into the superficial layer does not occur. Extension of the dorsal marginal zone begins in the late blastula stage with the rapid spreading of the apices of cells in this region and this continues until the onset of neurulation when rapid shrinkage begins. Extension and convergence of the dorsal marginal zone occurs by a rearrangement in which individual cells exchange neighbors and by a change in the shape of the cell apices. Regional differences in apical expansion are accompanied by differences in rate of anticlinal division of superficial cells such that cells in all sectors of the animal region and the marginal zone show similar patterns of decrease in apparent apical area. Shrinkage of the apices of bottle cells during blastopore formation is described. From this and other studies, a model of the cellular behavior of epiboly, extension and convergence is constructed and several hypotheses as to how these activities might generate the mechanical forces of the gastrulation movements are presented.
Re‐regeneration of lower jaws and the dental lamina in adult urodeles
Authors: Graver Heber T.
Published: February 2005

Transverse amputations were carried out through one‐third fully regenerated jaw segments and through normal tissue of the mandible on the same and opposite sides of the jaw in adults of Notophthalmus viridescens. Collectively the results suggest that, in adult urodeles, the mandible and the dental lamina can be replaced in an identical manner more than one time. Although the major histological events are the same in jaw regeneration and re‐regeneration, regrowth is more rapid in re‐regeneration. Extensively dedif‐ferentiating muscle fibers and skeletal elements contribute to a rapidly forming blastema in re‐regeneration. It appears that recently differentiated tissues of the regenerate have a higher capacity for regeneration than normal tissues amputated for the first time. Re‐regeneration of the jaw occurs by growth of the original regenerate cartilage which has undergone reorganization. In re‐regeneration, the skeletal elements exhibit no polarity and regrowth occurs in both directions, while the dental lamina possesses an anterior‐posterior polarity and can regrow in an anterior direction only. Information concerning the mechanisms involved in the regenerative events remain to be determined.
The jelly envelopes and fertilization of eggs of the newt, Notophthalmus viridescens
Authors: McLaughlin Ellen W. , Humphries A. A.
Published: February 2005

Fertilization in Notophthalmus viridescens is internal and involves passage of the sperm through five layers of egg jelly (J5‐J1, from outermost to innermost), each of which is secreted by a discrete region of the oviduct. Polyspermy is normal. Passage of the sperm through the jelly and into the egg was studied by a technique of artificial insemination similar to natural insemination, in that undiluted fluid from the vas deferens was applied directly to eggs with various layers of jelly present, followed by flooding with water three to five minutes later. In general, successful fertilization increased as the number of jelly layers increased; jellyless coelomic eggs were not fertilizable. Sperm passage through the jelly and into the egg usually occurs within one to three minutes. Upon hydration of the jelly, barriers to sperm penetration develop in layers J5 and J3. Changes in the egg jelly thus seem to be involved in the restriction of polyspermy to a low level.
The pineal‐paraphyseal complex of sea turtles. I. Light microscopic description
Authors: Owens David W. , Ralph Charles L.
Published: February 2005

The pineal‐paraphyseal complex of sea turtles is an impressively large structure which projects dorsally and anteriorly above the prosencephalon. The complex was examined by light microscopy in several age classes of green sea turtles (Chelonia mydas) and from juvenile loggerhead turtles (Caretta caretta). The paraphysis is extensively fused to the distal portion of the pineal body, suggesting an interrelated function for these two tissues. No duct or canal was observed connecting the pineal lumen to the third ventricle. Two pineal cell types are described which appear to correspond to the neuroglial supportive cells and the secretory rudimentary photoreceptor cells of other amniotic vertebrates. A possible luminal secretion in the form of apical protrusions is produced by the latter cell type. No typical photoreceptive outer segments were observed.
Comparative analysis of the intrinsic leg musculature of the American cockroach, Periplaneta americana (L.)
Authors: Alsop D. W.
Published: February 2005

The American cockroach has a total of 368 muscles inserting on the post‐coxal segments of its legs. By using a narrow morphological definition for delimiting individual muscles, it is shown (i) that the protrochanteral musculatures (23 muscles/leg) differ from the essentially identical meso‐ and metatrochanteral musculatures (24 and 26 muscles/leg) in number and disposition of extensors and in having a completely different flexor composition, and (ii) that the musculatures of the more distal segments of the legs are completely serially homologous, there being 2 muscles for moving each femur, 23 for each tibia, 7 for each first tarsomere, and 5 for each of the paired pretarsal claws. In all six legs, the trochanteral and tibial musculatures each contain single slender muscles that may be acting proprioceptively to measure the angular displacements between, respectively, the coxas and trochanters, and the femurs and tibias. Neurological and phylogenetic considerations are used to demonstrate why a narrow morphological definition should be employed, and why the widely used functional definition of Snodgrass ('35) is not only fallacious on evolutionary grounds, but also leads to making erroneous conclusions regarding the manner in which insect musculature is controlled by the insect central nervous system. Finally, it is hypothesized that the physiological limitations imposed by having an open circulatory system and the problems inherent in the neural control of large muscles may have been major evolutionary factors in forcing insects to use many slender muscles to control their body movements.
Studies on fish scale formation and resorption. I. Fine structure and calcification of the scales in Fundulus heteroclitus (Atheriniformes: Cyprinodontidae)
Authors: Yamada Juro , Watabe Norimitsu
Published: February 2005

Fine structure of the scales of Fundulus heteroclitus was examined by scanning and transmission electron microscopy. The concentric ridges of the scale surface were characterized by the presence of minute, highly calcified, denticles or tooth‐like processes. Needle‐shaped crystals of hydrox‐yapatite were precipitated not only in the osseous layer but in the intimate lamellae of the fibrillary plate except in portions just below the grooves. The calcification of the osseous layer was observed to proceed by filling the matrix with patches of crystals. The fibrillary plate appeared to calcify by invasion of crystals from the upper calcified zone into spaces between collagen fibers.
The intranuclear helices of Euplotes: Their substructure, localization, and apparent migration to the cytoplasm
Authors: Ruffolo John J.
Published: February 2005

Study of the fine structure of the macronucleus in Euplotes eurystomus, a ciliate protozoon, during various stages of the cell division cycle has yielded new information about intranuclear helices. They are frequently observed at the periphery of chromatin bodies or next to the nuclear envelope, and they appear to be a constituent of nucleoli. The fibril that forms a helix is about 11–15 nm thick, and torus profiles of helices cut in cross section are about 35 nm in diameter. In substructure the helix is composed of a thin strand 3–5 nm thick which is coiled to form the 11–15 nm fibril; so the helix is a super‐coiled structure. The intranuclear helices are present in the macronucleus throughout the cell cycle. They do not show obvious changes of relative abundance nor changes of relative localization in the nucleus, with one exception: they were never observed in the diffuse zone of replication bands. Evidence is presented indicating that nuclear helices migrate to the cytoplasm through nuclear pores. Although the chemical composition of the Euplotes intranuclear helices is unknown, information in the literature on similar helices in Amoeba indicates that they contain RNA and not DNA. The observations on Euplotes helices are consistent with a concept of “packaged” RNA for transport to the cytoplasm.
The morphology of the central nervous system of the barnacle, Semibalanus cariosus (Pallas)
Authors: Gwilliam G. F. , Cole E. S.
Published: February 2005

The central nervous system of the sessile barnacle, Semibalanus cariosus (Pallas), has been studied with the particular aim of determining the locations of neuron somata in relation to peripheral nerves. This was accomplished by tracing peripheral nerves using dissection and methylene blue staining techniques, histological methods, and by permitting cobaltous chloride to diffuse via axons into ganglia (“backfilling”).

The neuron maps resulting from the study reveal some well‐defined sub‐systems, a considerable degree of functional clumping of neuron somata, and some unexpected projections of neurons in the CNS. Neurophysiological studies based on these findings are in progress.
Development of the urostyle during metamorphosis in five species of anurans
Authors: Branham Arthur E. , List James C.
Published: February 2005

Normal development of the urostyle is described during late stages of metamorphosis in five species of anurans: Xenopus laevis (Daudin), Bufo americanus Holbrook, Pseudacris triseriata (Wied), Hyla chrysoscelis Cope, and Rana pipiens Schreber. The developing urostyle of all five species is composed of essentially the same cartilaginous elements: one pair of basidorsals above the notochord and the subtended hypochord. Among the five species there is variation in such details as the number of spinal nerve foramina and the degree of fusion of the basidorsals; however, both the hypochord and basidorsals are very similar in all five genera examined. Consideration of the literature suggests that contradictory descriptions of the developing urostyle result from (1) varied methods of study (alizarin‐staining of whole specimens or serial cross‐sections), (2) the variety of species examined, and (3) the particular stage of development of the tadpole described by an investigator.
Surface anatomy of branchial food traps of tadpoles: A comparative study
Authors: Wassersug Richard J. , Rosenberg Karen
Published: February 2005

Branchial food traps are regions of specialized secretory tissue in the tadpole pharynx, where suspended food particles are trapped in mucus.

Light and scanning electron microscopy were used to study branchial food traps from larvae of ten anuran families (36 species). Most anuran larvae from “advanced” (suborder Neobatrachia) families (e.g., Hylidae, Ranidae, Bufonidae) have distinct secretory pits at the posterior margins of the branchial food traps and secretory ridges elsewhere on these surfaces. The apices of columnar PAS‐positive, secretory cells are exposed on the floors of the secretory pits or in rows at the tops of the secretory ridges (secretory zone).

Tadpoles from most “archaic” (suborder Archaeobatrachia) families (Ascaphidae, Discoglossidae and Pelobatidae) either lack secretory pits, or have them poorly defined. They also lack secretory ridges but have columnar, mucus‐secreting cells whose apices are exposed in a seemingly random fashion in the branchial food traps. Rhinophrynus (Archaeobatrachia: Rhinophrynidae) has secretory ridges, but the apices of secretory cells are not arranged in rows at the tops of the ridges; instead they erupt singly or in small clusters on the epithelial surface, in a pattern similar to that in Ascaphus, the discoglossids and the pelobatids. It is proposed that the generalized condition for the branchial food trap mucosa is one where the apices of secretory cells are exposed haphazardly on a flat epithelium and the derived condition is one where the surface is organized into ridges. The morphology of the branchial food traps in Rhinophrynus suggests that, phylogenetically, ridges preceded the coalescing of secretory cell apices into distinct rows.

Pipidae and Microhylidae have unique patterns in the gross and microanatomy of their branchial food traps specific to their families.

Branchial food trap morphology relates to diets of tadpoles as well as to taxonomy. Obligate macrophagous (e.g., carnivorous) tadpoles, irrespective of family, tend to have reduced branchial food traps, regularly lack secretory ridges and, in extreme cases, lack columnar mucus‐secreting cells. Obligate microphagous forms (midwater suspension feeding of Xenopus, microhylids and Agalychnis), have straight parallel secretory ridges with narrow secretory zones and shallow troughs between the ridges.

Secretory ridges may help to form mucus strands in which food particles are trapped, but they are not essential for planktonic entrapment. The hydrodynamic implications of the various topographic patterns remain unclear.