bluuebunny/crossref_metadata_2025 huggingface dataset:
The early embryonic development of the jumping bristletail Pedetontus unimaculatus machida (Hexapoda: Microcoryphia, Machilidae)
Authors: Machida Ryuichiro , Nagashima Takayuki , Ando Hiroshi
Published: February 2005

The early development of Pedetontus unimaculatus from maturation to germ rudiment formation has been described by light and electron microscopy. Newly laid eggs of P. unimaculatus are in the metaphase of the first maturation division, and two successive maturation divisions produce two polar bodies. Nuclear divisions up to the eighth or ninth are accompanied by cytoplasmic divisions, and are holoblastic. Each resulting blastomere contains a single nucleus. Most cleavages are radial, but a few are tangential resulting in the formation of primary yolk nuclei. After the eighth or ninth nuclear division, cytoplasmic divisions are restricted to the egg periphery, and these later cleavages are superficial. Boundaries of blastomeres gradually disappear. Nuclei, which settle in the peripheral cytoplasm, proliferate and differentiate into blastoderm cells, and they also give rise to secondary yolk nuclei. A posterior circular region of blastoderm thickens and concentrates to form a germ rudiment 50–100 μm in diameter. During the formation of a germ rudiment the serosal cuticle begins to form.

A similar pattern of cleavage was observed in other species of the Machilidae belonging to four genera in two subfamilies (Machilinae, genus Haslundichilis; Petrobiinae, genera Pedetontus, Pedetontinus, Petrobiellus). The cleavage pattern of the machilids closely resembles that found in the myriapod groups, the Symphyla, Diplopoda, ana Pauropoda, as well as in the apterygote Collembola, but it differs from the purely superficial cleavage pattern characteristic of the apterygote Thysanura sensu stricto (Zygentoma) and the Pterygota.

It is concluded 1) that the pattern of early total cleavage changing later to superficial cleavage is a plesiomorphic character for the Antennata, and 2) that the purely superficial pattern is an apomorphic character within the Hexapoda.
The relationship of book lung and tracheal systems in the spider family uloboridae
Authors: Opell Brent D.
Published: February 2005

The book lung surface areas of representatives of six genera were measured and divided by spider prosomal and leg mass and by the product of prosomal length and width to obtain two indexes of book lung area. Both indexes are greatest in species that have the simplest tracheal systems and smallest in those with the most extensive tracheal systems. When species are ordered phylogenetically and the lung area indexes of their hypothetical ancestors computed, a transformational increase in lung area is indicated. Neither the lung area of a species nor its phylogenetic position is significantly related to the general moisture regime of its habitat. The number of leaves in a book lung is positively correlated with both spider size and total lung area. However, leaf number is not correlated with tracheal development and shows no transformational change.
Control of gastropod shell form via apertural growth rates
Authors: Hutchenson J. M. C.
Published: February 2005

This paper discusses and corrects ideas in Løvtrup and Løvtrup (J. Morphol. 197:53–62, '88) on how differential growth rates around the aperture cause the gastropod shell to coil at particular angles. The relationship between position relative to the shell apex and growth rate is derived. This lets us understand what information on relative growth rates around the aperture is sufficient to determine the shape of the logarithmic spiral that these growth rates generate. I argue that differential growth rates could not be physiologically controlled precisely enough to regulate apical angle; they passively follow, not actively direct, shell shape.
The digestive system of the lobster, Homarus americanus: II. Terminal hepatic arterioles of the digestive gland
Authors: Factor Jan Robert , Naar Michele
Published: February 2005

The digestive gland (midgut gland, hepatopancreas) of the American lobster, Homarus americanus (Decapoda: Nephropidae), is supplied with blood by the hepatic artery. Numerous branches, ending in terminal hepatic arterioles, permeate the organ and discharge blood into the hemal sinuses. Histological and ultrastructural studies show the arterioles to be elongate tubes that lie in the hemal spaces, interspersed among the digestive tubules of the digestive gland. The terminal hepatic arterioles comprise three distinct populations of cells: endothelial cells form the wall of the blood vessel; hemocytes circulate through the lumen of the vessel; and fixed phagocytes are attached to the outer surface of the endothelium. In addition, extracellular membranes form an endothelial intima that lines the lumen and a perforated membrane that covers the outer surface of the arteriole.
The digestive system of the lobster, Homarus americanus: III. Removal of foreign particles from the blood by fixed phagocytes of the digestive gland
Authors: Factor Jan Robert , Beekman Judith
Published: February 2005

The digestive gland (midgut gland, hepatopancreas) of the American lobster, Homarus americanus (Decapoda: Nephropidae), is permeated with terminal arterioles of the hepatic artery. Fixed phagocytes associated with the terminal hepatic arterioles removed two types of non‐biogenic, foreign particles (carbon particles and latex beads) that were injected into the blood. These cells play an important role in the cell‐mediated immunity of lobsters.
Venom apparatus and toxicity of the centipede Ethmostigmus rubripes (Chilopoda, Scolopendridae)
Authors: Ménez André , Zimmerman Kenneth , Zimmerman Shantay , Heatwole Harold
Published: February 2005

The venom apparatus of Ethmostigmus rubripes, a generalized predator, consists of the telopodites of the postcephalic segment, the basal article of which contains the venom gland. Within the gland, venom granules are concentrated in intracellular secretory granules, from which they are discharged into vacuoles in the cytoplasm of the secretory cells and thereafter by exocytosis into the lumen of the gland. A venom duct carries venom to the venom claw, which introduces it into prey via a subterminal pore on the outer curvature of the claw. Pits containing pegs, presumed to be sensory, are concentrated near grooves leading to a cutting ridge proximal to the point of the claw. The venom is toxic both to mammals and insects.
Topography and mechanics of the cupula in the fish lateral line. I. Variation of cupular structure and composition in three dimensions
Authors: Kelly James P. , van Netten Sietse M.
Published: February 2005

The cupula of the supraorbital neuromast in the lateral line canal of the clown knifefish contains vertical columns. In the central region of the cupula overlying the macula, these columns are densely packed, are relatively constant in size, and run from the base of the cupula to the surface of the cupula which is exposed to canal fluid. There are two types of columns, dark and light, which form elliptical compartments in planes of section that cut across the columns; the cupula therefore has the appearance of mosaic tile in such sections. The dark compartments contain tubules that extend from the base of the cupula at the junction with the macula to the top of the cupula. Each tubule is associated with the kinocilium of a single hair cell. The lateral parts of the cupula, not overlying the macula, also contain compartments, but these compartments differ in size and structure from those in the central region. In addition to the compartments, the central region of the cupula also contains spherical aggregates of droplets. These small aggregates, termed mora, are found principally in a layer within the central region of the cupula, but are also found outside this layer. Because of their light‐reflecting properties, the mora can be used for noninvasive optical measurements in vivo of the motion of the cupula.
Finite element analysis of a double membrane tube (DMS‐tube) and its implication for gastropod shell morphology
Authors: Morita Rihito
Published: February 2005

Molluscan shells, including those of Gastropoda, are formed by accretionary growth at the mantle edge. The mantle is a thin membrane of skirt‐like shape, which extends minutely beyond the aperture, and its edge adds a shell increment to the aperture margin so that each increment copies a configuration of the mantle edge at that time. Thus, regulation of shell morphogeny is almost equivalent to the factors which control the mantle form at the moment of shell growth. Form of the mantle skirt is considered to be kept in a state of balance between the force of its internal stress and forces acting on it such as fluid pressure or muscle contraction.

The expansion behavior of the mantle skirt has been numerically analyzed by using an elastic model (DMS‐tube), which represents the fundamental structure of the mantle tissue as a double membrane structure with internal springs (DMS). Four characteristic expansion patterns of the DMS‐tube have been detected: (1) general outward expansion; (2) developing a ridge‐like fold on an initial longitudinal protrusion of the tube edge; (3) drastic shift of the expanded state from a uniformly curved to an elliptical shape in outline, owing to the existence of a fixed boundary condition on the tube wall; and (4) constricted protrusion on the open region of the shell wall surrounding the DMS‐tube. These results have the potential for answering the following questions relating to the morphogenesis of gastropod shells. How does the mantle skirt usually make contact with the inner surface of the shell wall so as to ensure continuous accretion of shell materials to the aperture margin? What is the cause of spiral ridges? Why do open coiling or minimally overlapping shells have generally circular apertures, while shells with apertures overlapped by whorls have non‐uniformly curved apertural lips? What is the cause of long closed spines and why do they always appear on spiral ridges?
Mechanical constraints on aperture form in gastropods
Authors: Morita Rihito
Published: February 2005

Gastropod apertures reflect expanded states of their mantle edge under variable boundary conditions. The apertures are divided into two groups: apertures without distinct overlap zones (e.g., whorl overlap) and those with overlap zones. Each group follows a unique morphological rule. Apertures without overlap zones are generally circular in outline. Apertures with overlap zones are either elongated perpendicularly to the overlap zone or inflated abapically. Moreover, the latter abapically inflated apertures are generally accompanied by a straight section anterior to the overlap zone along the columellar axis (columellar part). Numerical analysis of an elastic double membrane tube whose main frame simulates the gastropod mantle indicates that these morphological rules are the products of mantle edge expansion under the condition that the head‐foot mass presses against the mantle edge in both the overlap zone and the columellar part. The mantle edge in these two zones is thus in a completely or partly fixed boundary condition at the moment of shell growth. The rest of the mantle edge is free to expand either symmetrically or asymmetrically. It is hypothesized that the head‐foot mass is a driving force for regulating the pattern of shell coiling and apertural shape.
Organ of Bellonci of an Antarctic crustacean, the marine isopod Glyptonotus antarcticus
Authors: Chaigneau Jean , Besse Colette , Jaros Peter P. , Martin Gilbert , Wägele J. Wolfgang , Willig Axel
Published: February 2005

The paired organ of Bellonci protrudes from the optic lobe of the giant Antarctic isopod, Glyptonotus antarcticus. It is linked to the cortex by a broad peduncle. No connection to the cuticle or “sensory pore organ” was found. A cluster of sensory‐like cells forms two outer ciliary segments branching into numerous microvilli with microtubules. The putative sensory somata are irregular in shape and contain a very high density of glycogen granules. The two outer segments sprout from two pits of the soma in different directions, forming a right angle. Glial cells wrap around the sensory cells and also delimit lacunae into which bundles of microvilli project. These lacunae contain electron‐dense granules of small size and with species‐specific patterns. Lacunae and dense granules show features typical of a degeneration process in the sensory cells.

This general morphology corresponds to the unilobular type of organ of Bellonci, known in other isopods; it differs from the plurilobular type with onion bodies found in other Crustacea.
Comparative morphology of female genitalia and the copulatory mechanism in Trypetimorphini (Hemiptera, Fulgoromorpha, Tropiduchidae)
Authors: Bourgoin T. , Huang J.
Published: February 2005

A comparative morphological study of the female genitalia in Trypetimorphini shows that Caffrommatissus trimaculatus has a monotrysian condition, while species of Trypetimorpha and Ommatissus are ditrysian. Dissection of Trypetimorpha biermani Dammerman in copula shows that spermatozoa are first deposited in the bursa copulatrix and probably are transferred secondarily into the spermatheca. Maintenance of copulatory position is achieved by the male's gonostyli gripping the female's VIII gonapophyses, by endosoma inflation, and by eversion of antero‐ventrally directed endosomal processes. Existence of the ditrysian condition in Fulgoromorpha is disputed and the presence of a copulatory‐duct has to be interpreted as a neoformation in Tropiduchidae, although within this group it could have evolved several times independently.
Developmental changes of the antenna and its neurons in the silkworm,Bombyx mori, with special regard to larval‐pupal transformation
Authors: Waku Yoshio
Published: February 2005

The larval antenna ofBombyx morihas 13 sensilla and about 52 sensory neurons in its distal portion. The axons form two nerve cords which unite in the cranial hemocoel to supply the brain as the olfactory nerve. The antennal imaginal disc, which is a thick pseudostratified epithelium continuous with the antennal epidermis, thickens markedly during the 5th instar by rapid cell proliferation. At the prepupal stage cell proliferation ceases and the disc everts to form a large pupal antenna. Simultaneously, an extensive cell rearrangement occurs in the antennal epidermis and the disc tissue becomes much thinner because of the abrupt expansion of antennal surface area. The two larval nerve cords thin down markedly by degeneration of axons, but they do not disintegrate totally even after the onset of pupation. The epidermis of the larval antenna forms the distal portion of the pupal antenna, while the imaginal disc forms the more basal portion. Development to the adult antenna occurs almost immediately after the onset of pupation; many adult neurons appear in the simple epidermis facing toward the thick outer side of the newly formed pupal cuticle. By 12 hours after the onset of pupation, these neurons align themselves in many transverse rows which are the first sign of the adult antennal configuration. Addition of these neuronal axons to the once‐thinned nerve cords causes resumed thickening of the cords during the first 24 hours and thereafter. Differentiation of adult sensilla begins in the next 24 hours and is almost completed at the third day of pupation, which requires a total of 10 days.
Annual cycle of the chromaffin cells of Triturus cristatus
Authors: Laforgia V. , Capaldo A.
Published: February 2005

Morphology of the chromaffin cells of Triturus cristatus during a complete annual cycle has been investigated. General ultrastructural characteristics are similar for all chromaffin cells, including numerous small mitochondria, well‐developed Golgi apparatus and rough endoplasmic reticulum with short cisternae. The primary difference among cells is the type of the chromaffin granules they posses. These are of two kinds: adrenalin (A) and noradrenalin granules (NA). Both types are simultaneously present in the chromaffin cells but with different ratios during the year. During December–January and May–August, NA granules largely prevail, while in September–November and February–April, A and NA granules are present in about equal quantities. The total quantity of catecholamine granules, however, is relatively constant throughout the year. These findings suggest that T. cristatus has a single type of chromaffin cell, the granule content of which varies according to different functional states. The catecholamines are apparently discharged by exocytosis.
Morphology and ultrastructure of the venom glands of the northern pacific rattlesnake Crotalus viridis oreganus
Authors: Mackessy Stephen P.
Published: February 2005

The venom gland of Crotalus viridis oreganus is composed of two discrete secretory regions: a small anterior portion, the accessory gland, and a much larger main gland. These two glands are joined by a short primary duct consisting of simple columnar secretory cells and basal horizontal cells. The main gland has at least four morphologically distinct cell types: secretory cells, the dominant cell of the gland, mitochondria‐rich cells, horizontal cells, and “dark” cells. Scanning electron microscopy shows that the mitochondria‐rich cells are recessed into pits of varying depth; these cells do not secrete. Horizontal cells may serve as secretory stem cells, and “dark” cells may be myoepithelial cells. The accessory gland contains at least six distinct cell types: mucosecretory cells with large mucous granules, mitochondria‐rich cells with apical vesicles, mitochondria‐rich cells with electron‐dense secretory granules, mitochondria‐rich cells with numerous cilia, horizontal cells, and “dark” cells. Mitochondria‐rich cells with apical vesicles or cilia cover much of the apical surface of mucosecretory cells and these three cell types are found in the anterior distal tubules of the accessory gland. The posterior regions of the accessory gland lack mucosecretory cells and do not appear to secrete. Ciliated cells have not been noted previously in snake venom glands.

Release of secretory products (venom) into the lumen of the main gland is by exocytosis of granules and by release of intact membrane‐bound vesicles. Following venom extraction, main gland secretory and mitochondria‐rich cells increase in height, and protein synthesis (as suggested by rough endoplasmic reticulum proliferation) increases dramatically. No new cell types or alterations in morphology were noted among glands taken from either adult or juvenile snakes, even though the venom of each is quite distinct. In general, the glands of C. v. oreganus share structural similarities with those of crotalids and viperids previously described.
Selected aspects of spinning apparatus development in Araneus cavaticus (Araneae, Araneidae)
Authors: Townley Mark A. , Horner Norman V. , Cherim Nancy A. , Tugmon Cathy R. , Tillinghast Edward K.
Published: February 2005

In the first half of this century, several workers observed small, seemingly glandular structures attached to the ampullate glands of spiders. Hence, they were termed accessory ampullate glands. In juvenile Araneus cavaticus, two pairs of these structures are present (starting at least with third instars), one pair attached to the major ampullate (MaA) glands and the other pair attached to the minor ampullate (MiA) glands. In adults, two pairs of accessory MaA glands and two pairs of accessory MiA glands are present. The two latter‐formed pairs of accessory ampullate glands are clearly the remnants of those ampullate glands which atrophy shortly after adulthood is reached. Morphological similarities between these accessory ampullate glands and those present in juveniles provide an indication that the latter also have their origin in functional ampullate glands.

A reduction in the number of ampullate glands following the last molt occurs in many spiders. The reason(s) for these reductions is unknown. In penultimate spiders close to ecdysis, we have observed that while the larger pairs of MaA and MiA glands (those that are retained in the adult) are undergoing molt‐related changes which apparently render them nonfunctional, their smaller counterparts are seemingly unaffected and functional. This raises the possibility that the principal role of the smaller ampullate glands may be to assume functions during the pre‐ecdysial period which are normally in the domain of the larger ampullate glands. If true, then their degeneration after the last molt would make economic sense.

The presence of cylindrical spigots in juvenile females starting with fourth instars is documented.
Acid phosphatase activity in mature secretory granules of the salivary gland ofBradysia hygida
Authors: Laicine E. M. , Fernandez M. A. , Sauaia H.
Published: February 2005

It is uncommon to find acid phosphatase activity in mature secretory granules. This paper demonstrates by light and electron microscope cytochemistry an acid phosphatase in mature secretory granules in the cells of one region of the salivary gland ofBradysia hygida(Diptera, Sciaridae). These secretory granules increase in number during larval development up to the beginning of the pre‐pupal period when they undergo massive exocytosis. Biochemical assays show that upon exocytosis of the majority of the granules the total acid phosphatase activity in the granular gland region drops to 10% of the maximum reached before exocytosis. During and after exocytosis, two other acid phosphatases, eletrophoretically different and much weaker in activity, become increasingly detectable in all gland regions. At the same time, in whole mount preparations, numerous tiny acid phosphatase‐positive granules (probably secondary lysosomes) become evident in all major cell types of the salivary gland. These results indicate that the S2 region of the salivary gland has mature secretory granules containing an acid phosphatase destined for exocytosis which is different in molecular properties from other acid phosphatases (likely lysosomal) made by the gland.
Oral disc muscles of anuran tadpoles
Authors: Carr Karen M. , Altig Ronald
Published: February 2005

The presence and configurations of the small, extrinsic muscle fibers of the M. mandibulolabialis superior in the upper labium and the M. inferior in the lower labium are described for 24 species in 9 families. Although several species possess only the M. inferior, or both the M. inferior and superior, none has only the M. superior. Some species without tooth rows possess the M. inferior, and microhylid tadpoles have a single‐stranded muscle different than the M. mandibulolabialis in each oral flap. The extrinsic oral muscles insert near the bottom of the inter‐row valleys behind each tooth ridge and the bases of marginal papillae lateral to the ends of tooth rows. Muscles do not extend to marginal papillae beyond the most distal row of teeth. Muscle contraction is presumed to rotate the teeth distally so that they contact the substrate at the proper working angle. This action probably occurs at full extension of the oral disc just before disc closure starts.
Ultrastructure of the tongue and anterior process of the sublingual plica in four species of venomous snakes
Authors: Mao Shou‐Hsian , Wang Jaang‐Jiun , Huang Shu‐Chuan , Chao Chung‐Faye , Chen Cheng‐Chen
Published: February 2005

The general histology and ultrastructure of the tongue and anterior process of the sublingual plica of four Taiwanese venomous snakes, the Chinese cobra (Naja naja atra), banded krait (Bungarus multicinctus), Taiwan habu (Trimeresurus mucrosquamatus), and bamboo snake (Trimeresurus stejnegeri stejnegeri) are described.

The tongue fork exhibits a mid‐dorsal invagination that broadens gradually toward its base. No mid‐ventral invagination is observed. The epithelial cells on both dorsal and ventral aspects of the tongue fork have large and small microfacets, micropores and microvilli. The cell size, distribution pattern of the large microfacets, and the number of small microfacets present on both sides of the fork are essentially the same within a species, but vary among species. The function of these ultrastructures on the cell surface might be for the capture of chemical substances. The large microfacets are raised areas of the cell membrane, each with a pale granule contained within. The chemical nature of the pale granule is not yet known. The small pores surrounding the large microfacets are shallow hollows left after the release of the pale granules from the microfacets. The basic histological pattern of the tongue fork of these species is similar, being composed of a mucosal layer outside and dense musculature inside. No taste buds are discernible.

The anterior processes are concave‐like expansions of the anteriormost portions of the sublingual plicae. The oblique folds and micropapillae of this organ might be helpful for receiving the chemicals collected on the tongue, when the tongue makes contact with the elevated processes. The elevated processes may penetrate the ducts of Jacobson's organs to effect the final transfer.
Skin structure and vascularization in the Antarctic notothenioid fish Gymnodraco acuticeps
Authors: Eastman Joseph T. , Hikida Robert S.
Published: February 2005

The scaleless notothenioid Gymnodraco acuticeps is a bottom dweller beneath the sea ice of McMurdo Sound, Antarctica. Gymnodraco experience unusual environmental conditions, including highly oxygenated subzero water. Skin morphology is evaluated with reference to its potential as a barrier to ice propagation and as a surface for cutaneous respiration. Light and electron microscopy and histochemistry reveal skin structure that is generally similar to that of other teleosts. In the epidermis, epithelial cells are arranged in nine to fifteen layers, and two types of mucous cells are also present. Large mucous cells are most common on external epidermal surfaces, whereas small cells are more frequent on internal epithelial surfaces. Epithelial cell junctions have extensive areas of desmosomes as well as interdigitations of the cell membranes, especially in the basal and midepidermis. The dermis consists of an exceptionally dense stratum compactum. The skin is thicker than that of Bovichtus, a scaleless temperate notothenioid from New Zealand. Mean skin thicknesses at sites on the trunk are 371–711 μm. With the exception of fins that contact the substrate, epidermal thickness between rays of most fins is 70–118 μm. The epithelial surfaces of the oral and branchial cavities are 27–50 μm thick. An unusual type of connective tissue is present beneath the epidermis of the pelvic fin. It contains abundant ground substance and is similar to mucous connective tissue of the mammalian umbilical cord. Perfusions of a microvascular filling agent reveal a moderately developed cutaneous vasculature. These vessels have the dimensions of capillaries (mean external diameter 11 μm). They are confined to the dermis and are more prominent on the head than on the trunk. The skin is secondary to the gills as a respiratory surface in Gymnodraco.
Ultrastructure of free neuromasts of Bathygobius fuscus (gobiidae) and canal neuromasts of Apogon cyanosoma (apogonidae)
Authors: Rouse G. W. , Pickles J. O.
Published: February 2005

Light and electron microscopic observations were made on the lateral line organs of the free neuromasts of the goby Bathygobius fuscus and the canal neuromasts of the cardinal fish Apogon cyanosoma. As in other lateral line systems, each neuromast consists of hair cells, supporting cells and mantle supporting cells, the whole being covered by a cupula. In B. fuscus the free neuromasts are mounted on papillae and have hair cells with stereocilia up to 2.5 μm long and a single kinocilium at least 25 μm long. Each neuromast is covered by a vane‐like cupula that can be divided into two regions. The central region over the sensory area contains columns of myelin‐like figures. These figures are absent from the outer region covering the mantle. The canal neuromasts of A. cyanosoma are diamond‐shaped with up to 1,500 hair cells. The cupula is unusual in having a channel that lies over the sensory region. The hair cells have up to 45 stereocilia, the tallest reaching 2.5 μm, and a kinocilium at least 5 μm long. Tip links are shown for the first time between rows of stereocilia of the hair cells of lateral line neuromasts. The presence of tip links has now been demonstrated for all acousticolateral hair cell systems.
Distribution and expression of two interactive extracellular matrix proteins, cytotactin and cytotactin‐binding proteoglycan, during development of Xenopus laevis. II. Metamorphosis
Authors: Williamson David A. , Parrish Elaine P. , Edelman Gerald M.
Published: February 2005

During metamorphosis of Xenopus laevis the extracellular matrix (ECM) proteins cytotactin and cytotactin‐binding (CTB) proteoglycan, and the cell adhesion molecules N‐CAM and Ng‐CAM, appear in highly restricted patterns determined by immunofluorescence histology.

During limb development, cytotactin appears from the earliest stages in a meshwork of ECM fibrils associated with migrating mesenchymal cells forming the limb bud. Cytotactin also appears in the ECM between the apical limb ectoderm and mesenchyme. Later, both cytotactin and CTB proteoglycan appear co‐localized within the central (prechondrogenic) limb mesenchyme. During chondrogenesis in these areas, cytotactin becomes restricted to perichondrium, while CTB proteoglycan is expressed throughout the cartilage matrix. The premyogenic mesenchyme surrounding the chondrogenic areas expresses N‐CAM. Later, N‐CAM is concentrated at the myogenic foci where cytotactin appears at sites of nerve/muscle contact and in tendons.

Expression of these molecules in the blastemas of regenerating limbs was also studied, and during development of the central nervous system, stomach, and small intestine.

Analysis of the expression patterns of cytotactin and CTB proteoglycan throughout development and metamorphosis reveals several consistent themes. The expression of these molecules is highly dynamic, often transient, and associated with key morphogenetic events. Cytotactin appears at multiple sites where cells undergo a transition from an undifferentiated, migratory phenotype to a differentiated phenotype. One or both molecules appear at several sites of border formation between disparate cell collectives, and CTB proteoglycan expression is associated with chondrogenesis.
Immuno‐Fluorescent analysis of follicular growth and development in whole ovaries of the Indianmeal moth
Authors: Zimowska Grazyna , Silhacek Donald L. , Shaaya Eli , Shirk Paul D.
Published: February 2005

The differentiation and growth of ovaries was analyzed using immuno‐fluorescence microscopy and then correlated with the changes in the external morphology of female pupae during metamorphosis of the Indianmeal moth, Plodia interpunctella (Hübner). Fourteen developmental points coincident with a daily change in the light:dark cycle were chosen for observation to describe the progress of cuticular, ovarian, and follicular development during metamorphosis. Follicular structure was examined in whole mounts of ovaries using an immuno‐fluorescent labelling technique. The growth of oocytes and nurse cell cap in terminal follicles was measured throughout ovarian development. A rapid increase in the relative size of the nurse cells began during the fourth scotophase and continued until the beginning of the sixth scotophase. Following the sixth scotophase, the relative size of the nurse cells decreased until they disintegrated prior to choriogenesis. Oocytes began to grow rapidly during the fifth scotophase, coincident with the initiation of vitellogenesis, and continued to grow until choriogenesis was initiated just after adult eclosion. The rate of follicular growth was related to the position of the follicle in the ovariole; the closer to the terminal position, the greater the rate of growth. Thus, at adult eclosion, each ovariole contained a linear array of follicles in progressive stages of development with the terminal follicles ready to begin choriogenesis.
Ultrastructural analysis of iridophore organellogenesis in a lizard, Sceloporus graciosus (Reptilia: Phrynosomatidae)
Authors: Morrison Randall L. , Frost‐Mason Sally K.
Published: February 2005

Transmission electron microscopy (TEM) data from the ultrastructure of lizard skin iridophores (reflective dermal chromatophores) are used to illustrate the organellogenesis of small rectangular reflecting platelets, which are the color‐generating components of these cells. During the development of reflecting platelets, crystals are deposited within double‐membraned vesicles from electron‐dense material located within the vesicles. The crystals are initially small but expand lengthwise eventually to fill the vesicle that contains them. The inner membrane then tightly surrounds the crystal whereas the outer membrane is much more loosely associated with the inner‐membrane‐bound crystal. These observations allow discussion of the possible origin of the precursor double‐membraned vesicles from endoplasmic reticulum (ER) and Golgi‐derived vesicles. A model is proposed that incorporates our findings and other published reports to explain the origin of the precursor double‐membraned vesicles via three alternative pathways.
Experimental morphology of the feeding mechanism in salamanders
Authors: Reilly Stephen M. , Lauder George V.
Published: February 2005

The subarcualis rectus I muscle (SAR) in the feeding mechanism of four tiger salamanders (Ambystoma tigrinum) was removed early in ontogeny and these individuals were allowed to complete metamorphosis. This procedure resulted in postmetamorphic tiger salamanders which differed from control individuals in the size (and thus force generating capacity) of the SAR muscle. The experimental manipulation of muscle ontogeny allowed a test of previous hypotheses of SAR function in postmetamorphic individuals. Multivariate analysis of variance for kinematic variables measured from high‐speed video records of feeding revealed that experimentally modified tiger salamanders did not protract the hyobranchial apparatus or project the tongue from the mouth during feeding. Removal of the SAR muscle resulted in significantly reduced hyobranchial elevation in the buccal cavity and reduced maximum tongue projection distance.
Movement of spermatozoa of Megaselia Scalaris (Diptera: Brachycera: Cyclorrhapha: Phoridae) in artificial and natural fluids
Authors: Curtis Sherill K. , Benner David B.
Published: February 2005

In artificial fluid, the spermatozoa move as linear cells or round up and rotate, propelled by spontaneous bending of their tails. Both linear and rounded cells can move forward and backward, but usually they move forward. The tails of all cells display, simultaneously, small primary bends and fewer, much larger secondary bends. Rounded cells form single secondary bends that remain unchanged as the cells rotate. They also form “node‐like” primary bends that travel posteriorly or anteriorly as the cells rotate forward or backward, respectively. Linear cells move their anterior regions into and out of focus in a cyclic fashion. They form rather prominent primary bends, as well as two to four secondary bends that travel posteriorly as the cells move forward. Secondary bends change in shape continuously and are not sinusoidal. The cells follow approximately linear trajectories, but the distances traveled per cycle, speeds, and secondary bending patterns are variable. When methyl cellulose is added to artificial fluid, linear movement is improved, and forward speeds are approximately tripled. The movement of spermatozoa in natural fluid of the female reproductive tract is remarkably less stereotyped than that of cells in artificial fluid. The cells, usually resembling straight lines or arcs, are very flexible and active. They lack obvious cyclic activity and double bending patterns. They are capable of moving both forward and backward and of adjusting their bending activity and speed within rather wide limits. Their average forward speed is about nine times faster than that of cells in artificial fluid.
Structure and ultrastructure of the epididymis of the viviparous lizard during the annual hormonal cycle: Changes of the epithelium related to secretory activity
Authors: Mesure M. , Chevalier M. , Depeiges A. , Faure J. , Dufaure J. P.
Published: February 2005

This study deals with the structure and ultrastructure of the epithelial cells of the lizard (Lacerta vivipara Jacquin) epididymis as related to secretory activity. The epithelium contains only two types of cells, secretory cells and basal cells. The secretory cells undergo an annual cycle which has been divided into 10 stages. In its most active secretory state, epithelium forms 65.3% of the organ volume. The secretory cell is a tall columnar cell (from 55 ± 3.4 μm to 74.3 ± 2.4 μm height) with a basal nucleus and a supranuclear cytoplasm almost entirely occupied by numerous large secretory granules (5 to 7 μm in diameter). At the ultrastructural level, secretory cells contain rough endoplasmic reticulum (RER), Golgi complex, and secretory granules at various stages of synthesis before being discharged into the lumen. Each granule is membrane‐limited and contains a spherical electron dense central core and a peripheral vacuole which varies in density. The secretory cell originates from small cubic cells (13.8 ± 0.7 μm) with few organelles (stage 1). The height of the cell increases gradually and free ribosomes appear first (stage 2), followed by scarce elements of RER (stage 3). The step preceding the secretion period (stage 4) is characterized by a conspicuous increase in volume of RER and Golgi complex. From stage 7 to stage 10, the cell undergoes a dramatic involution. After a transient hypertrophy of the RER, numerous autophagic vacuoles invade the cytoplasm. This degeneration can lead to a complete lysis of the cell and to its rebuilding after elimination of the greatest part of the cytoplasm. The volume of the epithelium falls to 15.6% of the total volume. With antibodies raised against the protein family which constitutes the main part of the secretion (L proteins of 19 kDa), it is shown by immunohistochemistry that these proteins are concentrated into secretory granules which are discharged into the lumen to finally bind to the heads of the spermatozoa.
Functional morphological interpretation of the distribution of muscle spindles in the jaw muscles of the mallard (Anas platyrhynchos)
Authors: Bout R. G. , Dubbeldam J. L.
Published: February 2005

The morphology and distribution of muscle spindles of jaw and tongue muscles in the mallard were examined in serial transverse sections of single muscles and in horizontal sections of a whole head. Our observations on spindle morphology are in agreement with previous descriptions of spindles in birds. Some spindles differ in their innervation and the pattern of intrafusal muscle fibers. The spindles of individual adductor and pterygoid muscles are distributed unevenly. Some adductor muscles lack spindles, whereas those of other muscles are confined to limited areas. Jaw opening muscles and extrinsic tongue muscles lack spindles. The stretch of extrafusal muscle fibers could be estimated from the difference in sarcomere length for birds with the beak open and closed. Not all muscle fiber groups are stretched evenly over the whole range of jaw opening. Only those fiber groups that are continuously stretched during jaw opening contain spindles.
Ultrastructural investigations of presumed photoreceptive organs in two Saccocirrus species (polychaeta, saccocirridae)
Authors: Purschke Günter
Published: February 2005

In addition to the pigmented ocelli, four different types of photoreceptor‐like organs without shading pigment have been found in Saccocirrus papillocercus and S. krusadensis. The sensory cells of these presumed ocelli are either ciliary or rhabdomeric with ciliary rudiments. With the exception of the multicellular type‐2 ocelli they are bicellular consisting of a sensory cell and a supportive cell. In each ocellus the supportive cell forms a thin cup‐shaped envelope around the sensory elements. In the type‐2 ocellus, 7 supportive cells form an ovoid cavity leaving openings through which dendritic processes of an equal number of sensory cells enter the cavity. The pigmented ocelli possess an ocellar cavity communicating with the exterior through a pore in the eyecup, ciliary rudiments in both sensory and supportive cell, and additional non‐photoreceptive sensory cells in the opening of the eyecup. The sensory organs show characteristic differences between the two species, such as presence or absence of a particular type of ocellus (type 2 is absent in S. krusadensis, type 3 in S. papillocercus), number of cilia in type‐4 ocelli, density of microvilli, number of non‐photoreceptive sensory cells in the pore of the pigmented ocellus, etc. These differences provide important characters which can be used for discrimination either of species or of subgeneric taxa in Saccocirrus. The phylogenetic significance of the different photoreceptive organs is discussed.
Abnormal craniofacial development in cyclopic salmonid fishes
Authors: Bolker Jessica A. , Thomson Keith S.
Published: February 2005

Different types and degrees of “spontaneous” and artificially induced cyclopic malformation in fishes are defined. Symmetrical cyclopia ranges from approximation of the eyes, to partial merger of the eyes in the midline, to complete cyclopia with a single median eye. It is always associated with dorsal displacement of the rostral‐nasal apparatus to the top of the head. Skeletal reorganization associated with symmetrical cyclopia is described for the first time, using hatchery material of Salmo gairdneri and S. trutta. Development of the nasal capsule is essentially normal, except for position; the trabeculae cranii remain in the normal position but show modified shape corresponding to the degree of cyclopia. The jaw apparatus is modified through anterior foreshortening, especially the upper jaws. The branchial apparatus is unaffected. The condition demonstrates that later morphogenesis of the nasal capsule and trabeculae cranii are independent of each other. Cyclopia appears to result from alteration of relative position and timing in developmental events in the head, especially the prosencephalon.
Liver ultrastructure of juvenile Atlantic salmon (Salmo salar)
Authors: Robertson John C. , Bradley Terence M.
Published: February 2005

Light and transmission electron microscopy of the liver of juvenile Atlantic salmon (Salmo salar) reveals a tubular arrangement of parenchymal cells, with biliary passages typically located at the center of tubules. Hepatocytes generally contain a single nucleus surrounded by a cuff of rough endoplasmic reticulum (RER), with many round to elongate mitochondria associated with the perinuclear RER. Whereas glycogen deposits are common and usually lie at the cell periphery, parenchymal cells seldom contain lipid droplets. Golgi complexes and heterogeneous dense bodies also occur in many hepatocytes, often in close proximity to bile canaliculi. Numerous microvilli from hepatocytes extend into the subendothelial space of Disse, which is also the location of stellate fat‐storing cells. Interhepatocytic macrophages, sometimes containing prominent phagolysosomes and residual bodies, are common in the liver. The intrahepatic biliary system consists of intercellular canaliculi, bile pre‐ductules, ductules, and ducts. In contrast to some other teleosts, the liver of the Atlantic salmon contains no intracellular bile canaliculi or Kupffer cells. The hepatic endothelium, arterioles, and perivenous regions are also described.
The vascular structure of the kidney of the neotenous axolotl and its metamorphosed counterpart
Authors: Ditrich H. , Splechtna H.
Published: February 2005

The renal vascular and glomerular structures of the kidney of neotenous and experimentally metamorphosed axolotls (Ambystoma mexicanum: Amphibia, Urodela) are investigated using light, transmission electron, and scanning electron microscopy of critical‐point dried specimens and vascular corrosion casts. The blood vascular system of the kidney in the axolotl is generally similar to that in other urodeles. The glomeruli are comparatively large and distincly ovoid (mean size 267 × 201 μm). Glomerular endothelial nuclei frequently bulge into the vascular lumen. Whereas the lamina rara externa and the lamina densa are quite uniform in diameter, the lamina rara interna shows a very irregular thickness with frequent interposed cellular processes. In the thyroxine‐metamorphosed animals, the glomerular surface decreased by a factor of approximately 36%; this was mainly due to the reduction of the glomerular diameter in the direction from vascular to urinary pole. No significant degeneration or new formation of renal tubules was observed during or after metamorphosis. A notable relative decrease in renal volume (approx. 57%) in the metamorphosed forms can be attributed mainly to a reduction in interstitial volume.
The comparative myology of the thigh and crus in the salamanders Ambystoma tigrinum and Dicamptodon tenebrosus
Authors: Ashley‐Ross Miriam A.
Published: February 2005

Variation in myology of the hind limb among salamanders has been poorly characterized. Nineteen major hind limb muscles of Ambystoma tigrinum (Ambystomatidae) and Dicamptodon tenebrosus (Dicamptodontidae) were studied to provide baseline descriptive data on hind limb myology in salamanders and to generate hypotheses of hind limb muscle function. Most superficial muscles of the hind limbs span multiple joints, including a unique three‐joint muscle, the ischioflexorius, that extends from the pelvic girdle to the plantar fascia. The deeper hind limb muscles spen single joints. No myological diffrences were observed between the hind limbs of A. tigrinum larvae and individuals that had just metamorphosed. Fully adult tiger salamanders that had been housed in terraria for many years had hypertrophied femorofibularis and ischiofemoralis muscles, a condition similar to that reported in Paramesotriton and Taricha, which engage in terrestrial locomotion. In contrast, adults of D. tenebrosus, which are also good walkers, possess a hypertrophied ischioflexorius muscle and a reduced femorofibularis. These regular myological diffences, and those described by previous workers for different salamnder taxa, may be associated with differences in life‐history traits, and in the case of A. tigrinum, with patterns of muscle use.