bluuebunny/crossref_metadata_2025 huggingface dataset:
Transformation of the intestinal epithelium of the larval anadromous sea lamprey Petromyzon marinus L. during metamorphosis
Authors: Youson J. H. , Horbert W. R.
Published: February 2005

The events in the transformation of the intestine of the larval lamprey into the adult intestine were followed through the seven (1–7) stages of metamorphosis in anadromous Petromyzon marinus L. Light and electron‐microscope observations demonstrated that the processes of degeneration, differentiation, and proliferation are involved in the transformation. In the anterior intestine, degeneration of cells and the extrusion of others into the lumen results in the disappearance of secretory (zymogen) cells and the decline in numbers of endocrine and ciliated cells. Larval absorptive cells, with a prominent brush border, are believed to dedifferentiate into unspecialized columnar cells with few microvilli. Degeneration and removal of cells occurs by both autophagy and heterography and cells extruded into the lumen in the anterior intestine are phagocytosed by epithelial cells of the posterior intestine. The loss of epithelial cells during transformation results in the folding and degradation of parts of the basal lamina and in an extensive widening of the lateral intercellular spaces in all parts of the intestine. As metamorphosis is a nontrophic period of the lamprey life cycle, the possible morphological effects of starvation on the intestinal epithelium are discussed.

The development of longitudinal folds is a consequence of the events of metamorphic transformation of the intestinal mucosa. Although an interaction between the epithelium and the underlying tissues is believed to be importent, the actual mechanism of fold development is unknown.

The intestinal epithelium of adult lampreys develops from surviving cells of the larval (primary) epithelium. Unlike the situation in amphibians, there does not appear to be a group (nest) of undifferentiated larval cells which differentiate into the adult (secondary) epithelium. Instead, in lampreys, columnar cells that persist through the degradative processes seem to be the source of absorptive and ciliated cells and probably are responsible for mucous and secretory cells.

Preliminary observations indicate that the intestinal epithelium of feeding adults is specialized into an anterior region which liberates a secretion, absorbs lipid, and possesses the machinery for ion transport. A posterior region absorbs lipid, secretes mucus, and likely is involved in some protein absorption.
Change of digastric muscle length in feeding rabbits
Authors: Muhl Zane F. , Newton John H.
Published: February 2005

An experiment was undertaken to measure directly the changing length of a jaw muscle during feeding in four intact, unanesthetized New Zealand White rabbits. Metal markers were implanted to define the anterior and posterior ends of the single belly of the digastric muscle and fluroscopic images were recorded on videotape while the animals fed on pelleted chow and carrot. Graphs of muscle length versus incisor separation were obtained by making measurements of single frames of the videotape record. The graphs revealed that when pelleted chow was being chewed the length of the diagastric muscle changed by no more than 9% of its greatest length; during the latter part of the closing stroke it changed very little. Incising and chewing carrot caused the digastric muscle to change in length continuously throughout the chewing cycle; incising carrot resulted in a 13% change in the length of the digastric muscle. The velocity of shortening is slightly less than one muscle length per second.
Ultrastructure of the ovary and oogenesis in the polychaete Capitella jonesi (Hartman, 1959)
Authors: Eckelbarger Kevin J. , Grassle Judith P.
Published: February 2005

Ultrastructural features of the ovary and oogenesis in the polychaete Capitella jonesi (Hartman, '59) have been described. The ovaries are paired, sac‐like follicles suspended by mesenteries in the ventral coelom throughout the midbody region of the mature worm. Oogenesis is unsynchronized and occurs entirely within the ovary, where developing gametogenic stages are segregated spatially within a germinal and a growth zone. Multiplication of oogonia and differentiation of oocytes into the late stages of vitellogenesis occur in the germinal region of the ovary, whereas late‐stage vitellogenic oocytes and mature eggs are located in a growth zone. Follicle cells envelop the oocytes in the germinal zone of the ovary and undergo hypertrophy and ultrastructural changes that correlate with the onset of vitellogenesis. These changes include the development of extensive arrays of rough ER and numerous Golgi complexes, formation of microvilli along the surface of the ovary, and the initiation of extensive endocytotic activity. Oocytes undergo similar, concomitant changes such as the differentiation of surface microvilli, the formation of abundant endocytotic pits and vesicles along the oolemma, and the appearance of numerous Golgi complexes, cisternae of rough ER, and yolk bodies. Yolk synthesis appears to occur by both autosynthetic and heterosynthetic processes involving the conjoined efforts of the Golgi complex and rough ER of the oocyte and the probable addition of extraovarian (heterosynthetic) yolk precursors. Evidence is presented that implicates the follicle cells in the synthesis of yolk precursors for transport to the oocytes. At ovulation, mature oocytes are released from the overy after the overlying follicle cells apparently withdraw. Bundles of microfilaments within the follicle cells may play a role in this withdrawal process.
Mastication in the tuatara,Sphenodon punctatus(reptilia: Rhynchocephalia): Structure and activity of the motor system
Authors: Gorniak G. C. , Rosenberg H. I. , Gans Carl
Published: February 2005

The masticatory pattern ofSphenodon punctatus, the sole remaining rhynchocephalian, now restricted to islands off the coast of New Zealand, has been analyzed by detailed anatomy, cinematography, cinefluoroscopy, and electromyography. Food reduction consists of a closing, crushing bite followed by a propalineal sliding of the dentary row between the maxillary and palatine ones. The large, fleshy tongue can be protruded to pick up small prey, and also plays a major role in prey manipulation. The rotational closing movement of the jaw, supporting the basic crushing movement, is induced by the main adductor musculature. It is followed by a propalineal anterior displacement relying heavily on the action of the M. pterygoideus. The fiber lengths of the several muscles reflect the extent of shortening. The most obvious modification appears in the M. pterygoideus, which contains a central slip of pinnately arranged short fibers that act a period different from that of the rest of the muscle; their action increases the power during the terminal portion of the propalineal phase. This also allows the animal to use its short teeth in an effective shearing bite that cuts fragments off large prey.

The action of single cusped dentary teeth acting between the maxillary and palatine tooth rows provides a translational crushing‐cutting action that may be an analog of the mammalian molar pattern. However, this strictly fore‐aft slide does not incorporate capacity for later development of lateral movement.
The structure of the chambered nautilus siphuncle: The siphuncular epithelium
Authors: Greenwald Lewis , Cook Clayton B. , Ward Peter D.
Published: February 2005

The siphuncle of the chambered nautilus (Nautilus macromphalus) is composed of a layer of columnar epithelial cells resting on a vascularized connective tissue base. The siphuncular epithelium taken from chambers that have not yet begun to be emptied of cameral liquid has a dense apical brush border. The great number of apical cell junctions (zonula adherens) compared to the number of nuclei suggests extensive interdigitation of these cells. The perinuclear cytoplasm of these preemptying cells is rich in rough endoplasmic reticulum. The siphuncular epithelium of both emptying and “old” siphuncle (which has already completed emptying its chamber) both show little rough endoplasmic reticulum but do contain extensive systems of mitochondria‐lined infoldings of the basolateral plasma membranes. Active transport of NaCl into the extracellular space of this tubular system probably entrains the water transport involved in the chamber‐emptying process. Both emptying and old siphuncular epithelium also show large basal infoldings (canaliculi) continuous with the hemocoel, which appear to be filled with hemocyanin. The apical cell junctions of emptying and old siphuncular epithelium contain septate desmosomes that may help to prevent back‐flow of cameral liquid into the chambers.
Structure and development of the larval visual system in embryos of Lytta viridana leconte (coleoptera, meloidae)
Authors: Heming B. S.
Published: February 2005

At hatching (252–264 hr. at 25 ± 0.5°C), the visual system in larvae of Lytta viridana consists of paired stemmata, stemmatal nerves, optic neuropiles, and inner and outer imaginal optic lobe anlagen. It originates between 64 and 72 hr. with invagination of an optic lobe primordium in the side of each protocephalic lobe. These primordia later differentiate into protocerebral ganglion cells and the imaginal optic lobe anlagen. Each stemma arises at 72 hr. from epidermis below and behind the optic lobe invagination and subsequently becomes cupshaped, closes over, and differentiates. At hatching, it consists of a planoconvex corneal lens, a corneagenous layer, and an everse retina of numerous, pigmented retinular cells, each with a terminal rhabdomere. Between 96 and 104 hr, proximal ends of the retinular cells grow posteromedially into a transverse, horizontal fold in the posterior wall of each optic lobe invagination and along its length to the protocerebral neuropile, which they contact by 112 hr. As the brain withdraws posteriorly within the head, these axons elongate correspondingly. Sheath cells of stemmata and stemmatal nerves descend either from protocerebral perineurium or the optic lobe primordia.

Structure and development of the larval visual system in L. viridana are compared with those of other insects and its various components are shown to be homologous throughout the Insecta. However, the stemmata of this insect more closely resemble the atypical imaginal eyes of male scale insects than the photoreceptors of other holometabolous larvae–a similarity arising through convergence.
Integumentary appendages of chelonians
Authors: Winokur Robert M.
Published: February 2005

The head and neck of four families of turtles, the Chelydridae, Kinosternidae, Pelomedusidae, and Chelidae, possess a diverse assemblage of skin appendages. Appendages are termed barbels when they occur in the gular region and tubercles when they occur other places. The appendages consist of protrusions of the dermis and epidermis and are devoid of such specializations as taste buds or neuromasts. They lack skeletal tissue, muscle, or erectile tissue. Methylene blue and silver staining techniques reveal a high density of nerves. The occurrence and morphology of barbels and tubercles suggest that they function as mechanoreceptors. Skin appendages are most elaborate in carnivorous species and reach maximum development in two distantly related convergent species: Macroclemys temmincki (Chelydridae) and Chelus fimbriatus (Chelidae). Skin appendages also help provide camouflage and disruptive effects on the head. The increase in surface area produced by the appendages may be important in aquatic respiratory gas exchange in some species within the Kinosternidae.
A model for comparison of masticatory effectiveness in primates
Authors: Sheine Wendy S. , Kay Richard F.
Published: February 2005

A model is presented to express how effectively animals increase the exposed surface area of their food by chewing. It includes a coefficient of masticatory effectiveness (E) the value of which increases with effectiveness of exposing new food surface area with each chew. Humans and other species of primates differ significantly in their values of E; among the nonhuman primates studies, Lemur catta has a higher coefficient than Lemur fulvus, and both have higher coefficients than either Varecia variegatus or Galago crassicaudatus argentatus. The differences among the coefficients to these prosimians are correlated with variations in specific features of the molar morphology.

Of six lower molar shearing crests considered, the relative length of the post‐metacristid correlates most highly with the coefficient of masticatory effectiveness for the prosimian species. Also, among comparable‐sized prosimians, E correlates significantly with the absolute postmetacristid length. Both these findings indicate that the relative size of molar shearing crests is related significantly to how effectively an animal chews its food. There are also implications for an adaptation to a high‐fiber diet.
The functional morphology of the musculature of squid (Loliginidae) arms and tentacles
Authors: Kier William M.
Published: February 2005

The arms and tentacles of squid (Family Loliginidae: Sepioteuthis sepioidea (Blainville), Loligo pealei (LeSueur), Loligo plei (Blainville), Loliguncula brevis (Blainville)) do not possess the hardened skeletal elements or fluid‐filled cavities that typically provide skeletal support in other animals. Instead, these appendages are made up almost entirely of muscle. It is suggested here that the musculature serves as both the effector of movement and as the skeletal support system itself.

High‐speed movie recordings were used to observe prey capture by loliginid squid. Extension of the tentacles (1 pair) during prey capture is probably brought about by contraction of transverse muscle fibers and circular muscle fibers. Contraction of longitudinal muscle fibers causes retraction of the tentacles. Torsion of the tentacles during extension may be the result of contraction of muscle fibers arranged in a helical array. The inextensible but manipulative arms (4 pairs) may utilize a transverse muscle mass to resist the longitudinal compression caused by contraction of the longitudinal muscles which bend the arms. A composite connective tissue/muscle helical fiber array may twist the arms.
Pharyngeal mastication and food transport in the carp (Cyprinus carpio L.): A cineradiographic and electromyographic study
Authors: Sibbing Ferdinand A.
Published: February 2005

Cyprinids constitute the largest fish family and are characterized by their pharyngeal teeth. The masticatory mechanism is still poorly understood. The complex of structures that determine the movements of pharyngeal teeth and chewing pad in the carp (Cyprinus carpio L.) is analyzed. Activities in 16 head muscles of a free‐swimming carp were recorded. X‐ray cinerecordings, synchronized with electromyograms, were made of the intake, transport, mastication, and deglutition of radiopaque food pellets. Metal markers allowed a detailed movement analysis.

Masticatory cycles are bilaterally synchronous and show distinct crushing and grinding patterns. Direct masticatory muscles that suspend and connect the pharyngeal bones steer and stabilize the masticatory movements. Baudelot's ligament, between skull and pectoral girdle, is applied as fulcrum, effects a crucial shift of the rotation axis of the pharyngeal jaw, and transforms crushing into grinding; simultaneous abduction lengthens the grinding stroke. Body muscles supply indirectly the power for mastication; they also appear to be regulated more distantly. The epaxial muscles lift the skull and thereby the levators of the pharyngeal bones, thus transmitting high forces to the teeth. They also stretch the levator of the bone as soon as occlusion is reached and thus optimize its production of forces during grinding. The hypaxial muscles retract the pharyngeal bones indirectly during grinding and power the teeth in sliding. The chewing pad, previously assumed to be motionless, rotates rostroventrad with the skull and intensifies grinding.

Respiration and mastication are mutually related. The extensive movements of the pharyngeal bones are permitted only by the simultaneous expansion of the buccopharynx and a slide‐coupling in the branchial floor. Muscular pads that line the pharynx are shown to transport food toward the teeth. The constrictor pharyngis effects deglutition.

Natural food, intestinal contents, and feces of the carp were analyzed with respect to the capacity for distinct masticatory operations. During the experiments pellets, barley, and worms were fed. The carp is specialized for polyphagy and this appears to be based on the profiles of the heterodont teeth rather than on drastic changes in the two preprogrammed activity patterns. Comparison of the pharyngeal jaw system in the carp and higher teleosts emphasizes the structural design for the application of large forces in this cyprinid.
Histology and histochemistry of the parotid and the principal and accessory submandibular glands of the little brown bat
Authors: Pinkstaff Carlin A. , Tandler Bernard , Cohan Richard P.
Published: February 2005

The parotid and the principal and accessory submandibular glands of the little brown bat, Myotis lucifugus (Vespertilionidae), were examined using light microscopy and staining methods for mucosubstances. The parotid gland is a compound tubuloacinar seromucous gland. Parotid gland secretory cells contain both neutral and nonsulfated acidic mucosubstances. The principal and accessory submandibular glands are compound tubuloacinar mucus‐secreting glands. They contain somewhat atypical mucus‐secreting demilunar cells that often appear to be interspersed between mucous tubule cells. The mucous tubule cells in both the principal and accessory submandibular glands contain sulfomucins. Demilunar cells of the principal submandibular gland contain moderate amounts of nonsulfated acidic mucosubstances, but the corresponding cells of the accessory submandibular gland contain considerable neutral mucosubstance with very little acid mucosubstance. Intercalated ducts composed of cuboidal or low columnar epithelial cells are present in all three glands. Striated ducts in all glands are composed of columnar cells whose apices bulge into the ductal lumina. Excretory ducts are composed of simple columnar epithelium, with occasional basal cells that suggest a possible pseudostratified nature. The cells of the excretory ducts also have bulging apices. All duct types contain apical cytoplasmic secretory material that is a periodic acid‐Schiff positive, neutral mucosubstance. Ductal apical secretory material is more evident in intercalated and striated ducts than in excretory ducts.
Development and metamorphosis of the feeding apparatus of the stone crab, Menippe mercenaria (brachyura, xanthidae)
Authors: Factor Jan Robert
Published: February 2005

Analysis of the feeding apparatus of the stone crab, Menippe mercenaria (Brachyura, Xanthidae), has demonstrated that substantial internal and external morphological alterations occur at metamorphosis and suggests that the mastication of food shifts from the mandibles to the gastric mill at that time. These changes correspond to the changes in environment and diet that take place at metamorphosis, when the previously planktotrophic larvae begin benthic life.

A detailed account of the structure and development of the mandibles is presented. The mandibles of all zoeal stages are similar: The incisor process has a series of teeth and denticles and the prominent molar process appears to be well adapted for grinding food. Megalopal mandibles are transitional but have the form that is typical of all subsequent stages: The expanded incisor process is rounded and toothless and the molar process is less prominent and has lost its grinding denticles. The cardiac stomach of the zoeal stages has no gastric mill; the medial and lateral teeth of the mill first appear in the megalopa.

A very simple procedure is described for preparing larval mandibles for scanning electron microscopy using the molted exoskeletons from larval rearing experiments.
Origin and formation of the royal fat body of the higher termite queens
Authors: Han Sun Heat , Bordereau Christian
Published: February 2005

The formation of the royal fat body was studied by electron microscopy in three species of higher termites (Macrotermes bellicosus, Macrotermes subhyalinus, and Cubitermes fungifaber). The swarming alate imago has a storage fat body typical of most insects. In non‐physogastric young queens, during the fasting period, the adipocytes deplete their reserves and then, along with the increased vitellogenesis, acquire protein‐synthesizing structures (R.E.R.). During the development of physogastry they progressively specialize in protein synthesis and secretion and undergo many cell divisions. The cytological change is paralleled by a spatial reorganization of the fat body. Observations on the transformation of imaginal adipocytes into royal adipocytes show that the royal fat body is derived from the imaginal fat body and not from the tracheal cells as previously claimed.
Histological and enzyme histochemical studies on the nephrons of the freshwater fishes, Cyprinus carpio and Carassius auratus
Authors: Endo Makoto , Kimura Masao
Published: February 2005

The nephrons of carp (Cyprinus carpio) and goldfish (Carassius auratus) were examined histologically and also histochemically for enzymes. In both species the distal and collecting tubules have much wider lumens than do the other renal tubules; thus urine probably flows more slowly in these larger tubules. Enzyme histochemistry shows that epithelium of the neck and proximal and intermediate tubules respires anaerobically. whereas that of the distal and collecting tubules respires aerobically. The distribution of Na‐K‐ATPase in the distal and collecting tubules indicates that they also transport sodium actively. The slow flow of urine and the energy produced by aerobic metabolism probably increase the efficiency of active transport.
Gut‐Associated lymphoid tissue (GALT) in the amphibian urodele Pleurodeles waltl
Authors: Ardavin C. F. , Zapata A. , Villena A. , Solas M. T.
Published: February 2005

Even though salamanders are supposed to lack intestinal lymphoid tissue, Pleurodeles waltl shows lymphoid aggregates throughout the gut, especially in the small intestine, as cell infiltrates in the lamina propia. They have a phylogenetic significance in relation to the existence of an intestinal immunologic barrier in vertebrates.
Setiferous structures of male coleoptera
Authors: Faustini D. L. , Halstead D. G. H.
Published: February 2005

A scanning electron microscopy study was made of the male setiferous sex patches and analogous structures in 11 families of Coleoptera (Anthribidae, Bruchidae, Ciidae, Cleridae, Coccinellidae, Dermestidae, Leiodidae, Ptinidae, Staphylinidae, Tenebrionidae, and Ostomatidae). These secondary sexual characters appear to have several features in common including relatively long, often ridged, setae, cuticular ducts (frequently cribriform pore plates), and the production of a secretion. It is suggested that these structures may all be concerned with the production, release, and dissemination of pheromones.
An electromyographic study of the function of the jaw adducting muscles inVaranus exanthematicus(varanidae)
Authors: Smith Kathleen K.
Published: February 2005

The function of major features of the skull ofVaranus exanthematicusduring feeding was examined using cineradiography and electromyography. During the initial stages of feeding,Varanusgrabs and orients a prey item in the mouth with no mastication, tearing of the prey, or killing bite. Ingestion is through a highly stereotyped movement, inertial feeding. The tongue plays no role in food transport. Once the prey is in the pharyngeal region, the hyoid apparatus squeezes the prey into the esophagus and stomach. Activity of jaw adducting muscles during prey orientation and inertial feeding is strikingly different. In prey orientation, the adductor musculature is active over long periods, and intermuscular differentiation and unilateral activity are common. During these phases the musculature is producing force against the resistance of the prey item held between the teeth. In inertial feeding, the jaw musculature functions to close the jaws rapidly against little resistance. A consistent pattern of intramuscular differentiation is present, with some portions of the musculature being active during both jaw opening and closing. Activity of the Mm. adductor mandibulae externus and pterygoideus is indistinguishable. Neither meso‐ nor metakinetic movement was observed during inertial feeding; resolution of interacranial movement was less certain during power phases. The quadrate moved during jaw opening and closing in inertial feeding. However, its movement was not linked with that of the palatomaxillary segment. These data are discussed in three contexts: cranial kinesis, intramuscular differentiation, and the mechanics of whole muscles.
An ultrastructural analysis of the mature spermatozoon of Anguispira alternata (say) (pulmonata, stylommatophora)
Authors: Atkinson James W.
Published: February 2005

Mature spermatozoa from the hermaphroditic duct of adult snails were examined using various techniques of light microscopy as well as scanning and transmission electron microscopy. The sperm are approximately 557 μm in length including a dextrally spiral head approximately 13 μm long. The head consists of an electron‐dense nucleus sculptured into a double‐ridged spiral and an acrosome projecting approximately 0.45 μm beyond the apex of the nucleus. The acrosome consists of a membrane‐bound vesicle approximately 0.1 μm in diameter and a column of homogeneous material which extends along one side of the terminal spiral of the nucleus. This material is separated from the nucleus by the nuclear envelope. The neck region, though similar to that found in other pulmonates, possesses a unique coiled structure surrounding the central doublet of the axoneme. The midpiece axoneme possesses a 9+9+2 configuration anteriorly grading into a 9+2 pattern for the majority of its length. There are three mitochondrial helices – one primary and two secondary – in the midpiece. Only the primary helix persists throughout the midpiece.
The ultrastructure of spermatogenesis in Labidocera aestiva (copepoda: Calanoida)
Authors: Blades‐Eckelbarger P. I. , Youngbluth M. J.
Published: February 2005

The fine structure of spermatogenesis is described for the marine calanoid copepod Labidocera aestiva. The mature spermatozoon is a slightly flattened, disc‐shaped cell without a flagellum or an acrosome.

Primary spermatocytes in first meiotic prophase are characterized by large nuclei showing progressive condensation of chromatin. The cytoplasm contains free ribosomes, numerous mitochondria, cytoplasmic vesicles, centrioles, and perinuclear nuage. Densely staining cisternae are associated with the nuage of pachytene and diplotene primary spermatocytes. This association may represent the temporary differentiation of an acrosome. Synaptonemal polycomplexes are frequently present in the nuclei of zygotene, pachytene, and diplotene primary spermatocytes. Many of the intercellular bridges which join the germ cells throughout spermatogenesis appear occluded by systems of transverse membranous cisternae. After the second meiotic telophase, spermatids are incorporated into nongerminal accessory cells that may facilitate the release of spermatids from the testis and regulate the rate of spermatogenesis by phagocytosis.

During spermiogenesis the mitochondria become closely applied to the nuclear envelope, the nuclear envelope fragments and forms an elaborate membrane complex, a pentalaminar plasma membrane develops, and electron‐dense material accumulates on the inner and outer surfaces of the plasma membrane in the mature spermatozoon.
Arterial retia related to supply of the central nervous system in two small toothed whales– narwhal (Monodon monoceros) an beluga (Delphinapterus leucas)
Authors: Vogl A. W. , Fisher H. D.
Published: February 2005

We have studied the comparative anatomy of arterial plexuses (retia mirabilia) related to supply of the central nervous system in two closely related species of toothed whales – narwhal (Monodon monoceros) and beluga Delphinaterus leucas). In both species, retia originate from major vessels in the neck, thorax, and lumbar regions, then extend into the neural canal and cranium to supply the spinal cord and brain. The system generally consists of arteries embedded in á matrix of fatty connective tissue. Constituent vessels are only occasionally reated to veins or venous sinuses. Though retial anatomy is similar in the two species, there are two related features that appear species specific: (1) amount of retia originating from the supreme intercostal arteries and (2) thoracic retial size. Both are larger in the narwhal, as are values for hematocrit and hemoglobin concentration, which, in this study, we use as indices of diving ability. Our data are consistent with the hypothesis that the retia are in some way linked to diving ability. The nature of this link is not known; however, we discuss our results in the context of the most popular hyotheses of retial function.
Hamster nasal glands: Their structure, sialic acid content, and vulnerability to actinomycin D
Authors: Adams Don R.
Published: February 2005

This study examines the structure of mucosal glands in the walls of the hamster maxillary recess, compares the histochemical appearance of nasal glands to their sialic acid content, and determines the vulnerability of nasal glands to actinomycin toxicity. Observations were made on plastic‐embedded tissue with light and transmission electron microscopes. Determinations of total sialic acid in mucosal samples were conducted with thiobarbituric acid. Experimental hamsters were administered 0.2 μg of actinomycin D (IP)/gm body weight/day for five days. Types of granules present in the lateral nasal gland (LNG) and glands of the maxillary recess (MRGs) include: 2.0 μm lightly basophilic, lightly electron‐dense granules and 1.5 μm strongly basophilic, electron‐dense granules in the same acinar cell type in both the LNG and MRGs; 1.5 μm metachromatic granules in some acinar cells of the LNG; 1.0 μm moderately electron‐dense granules in cells of MRG ducts; and 0.7 μm electrondense granules in cells of LNG intercalated ducts. Acid glycoproteins, demonstrable by histochemistry, are present in the LNG but not in the MRGs. However, the total sialic acid content of tissues from MRG tissue is greater than that of other tissues measured. A minor number of LNG acini, those with metachromatic granules, have branching basal cytoplasmic projections. Many dark cells are present in striated ducts of the LNG. Histological alteration due to actinomycin‐D toxicity, conspicuous in parotid salivary parenchyma, is greater in MRG than in LNG tissue.
Osteocranial development in the viviparous surfperch Amphistichus argenteus (pisces: Embiotocidae)
Authors: Morris Steven L. , Gaudin Anthony J.
Published: February 2005

The development of the cranial and branchial skeleton of the surfperch Amphistichus argenteus, a member of the family Embiotocidae, is described, and phylogenetic and functional aspects of the skull development of this species are discussed. The earliest bones to appear are those dermal elements of the branchial skeleton involved with feeding, and the bones, both dermal and endochondral, located in the basicranial region of the neurocranium. These are followed by dermal bones associated with the lateral line system and finally by the remainder of the bones of the branchial skeleton and the cartilaginous bones of the otic capsules. The last bone to develop is the ethmoid.
Transformations of osteoclast phenotype in ia rats cured of congenital osteopetrosis
Authors: Marks Sandy C. , Schneider Gary B.
Published: February 2005

The reduced bone resorption characteristic of osteopetrosis is accompanied in the incisors‐absent (ia) rat mutation by a significant increase in osteoclasts of inactive (mutant) phenotype. Restoration of bone resorption in ia rats by transfer of spleen cells from normal littermates is preceded by a transformation of osteoclasts from mutant to normal phenotype.

In this investigation the proportions of osteoclasts of normal phenotype have been determined by light microscopy in untreated ia and normal rats and in ia rats treated with various cell populations from normal rats. Significant increases in numbers of osteoclasts of normal phenotype were seen in the mutant skeleton soon after cell treatments that eventually restored bone resorption and cured the disease. No changes in osteoclast phenotype were seen after cell transfers that did not cure the disease.

These data establish transformation of osteoclast phenotype as an early event in the recovery from osteopetrosis and suggest that determination of osteoclast phenotype is a reliable predictor of the success of normal cell populations to restore bone resorption in this mutation.
Functional morphology of the head of the inertial suction feeding butterflyfish, Chaetodon miliaris (perciformes, chaetodontidae)
Authors: Motta Philip Jay
Published: February 2005

The structure and mechanism involved in jaw movements are described for an inertial high‐speed suction feeding fish, Chaetodon miliaris. Jaw biomechanics were studied by (1) manipulation of live and fresh‐killed specimens, (2) electrical muscle stimulation of anesthetized live specimens, (3) connective tissue severance experiments of fresh‐killed and live anesthetized specimens, and (4) cine photography of live unimpaired and surgically impaired specimens.

Three couplings appear to be involved in jaw opening: a levator operculi‐opercular‐interopercular‐mandible coupling; and epaxial complex and/or hypaxial/sternohyoideus complex‐hyoid apparatus‐uncontracted protractor hyoideus‐mandible coupling. Jaw opening, protrusion, closing of the protruded mouth, and jaw retraction occur in 60–110 msec. Jaw protrusion coincides with mandible depression during opening of the mouth. Closure of the protruded mouth is apparently the result of contractions of pars A1 and A2 of the adductor mandibulae muscle. Pars A3 and Aw may induce retraction of the jaws in the closed‐protruded state. Jaw closure in the retracted, nonprotruded state may involve all branches of the adductor mandibulae.

The importance of these findings is discussed in light of previous studies as are some proposed functions of jaw protrusion in this species.
Structural characterization of the hemocytes of Plodia interpunctella
Authors: Beeman Sylvia C. , Wilson Marijo E. , Bulla Lee A. , Consigli Richard A.
Published: February 2005

Six types of hemocytes were identified in fifth instars of the Indian meal moth, Plodia interpunctella. The morphology of these cells was characterized by phase contrast and electron microscopy, with Sudan black B, Giemsa, Janus green B, and periodic acid‐Schiff staining. Reaction of the hemocytes with seven fluorescing lectin conjugates revealed distinctive binding patterns by their plasma and nuclear membranes and cytoplasmic inclusions. A direct line of descent from prohemocytes to plasmatocytes to granulocytes is suggested from these morphological observations.
Extraordinary fossorial adaptations in the oligocene palaeanodonts Epoicotherium and Xenocranium (Mammalia)
Authors: Rose Kenneth D. , Emry Robert J.
Published: February 2005

New fossils of the rare Oligocene mammals Xenocranium and Epoicotherium add information on their skulls and provide the first information on their postcranial skeletons. These epoicotheres, the latest surviving palaeanodonts, have numerous fossorial adaptations and must have been predominantly subterranean. Their skeletal specializations are similar to, and equal or surpass in degree of development, those of most living fossorial mammals.

Principal modifications of the skull are the expanded, domed occiput with broad lambdoid crests, hypertrophy of the malleus‐incus and related changes in other ear components, reduced eyes, and (in Xenocranium) a flaring, upturned, spatulate snout. The neck was strengthened by synostosis of the 2nd through 5th cervical vertebrae. The forelimb elements have exaggerated crests, processes, and fossae for muscles used in digging or in stabilizing certain joints. The scapula has a high, stout spine with bifid acromion, a “secondary spine,” and an expanded postscapular fossa for attachment of the teres major muscle. The humerus has an elongate pectoral crest, large lesser tuberosity, long entepicondyle, and large hooklike supinator crest. The enormous incurved olecranon process of the ulna provided insertion for the massive triceps and origin for the carpal and digital flexors, and the latter gained mechanical advantage by incorporating in its tendon a large carpal sesamoid. In the greatly shortened hand, digit three is largest, with its metacarpal and proximal phalanx fused and its claw‐bearing ungual‐phalanx very large.

These traits indicate that Xenocranium and Epoicotherium were among the most specialized “rapid‐scratch” diggers ever to evolve. Their remarkable convergence to chrysochlorids reflects a similar mode of digging, with extensive use of the snout for loosening and lifting soil when making shallow foraging burrows. For deeper burrowing, the forelimbs probably loosened the soil while the rear limbs moved it behind. Like many extant subterranean mammals, Xenocranium and Epoicotherium were essentially sightless, but they were specialized for low frequency sound reception. Their extinction may have been due to a combination of environmental change and competition with other fossorial animals, such as proscalopine insectivores and rhineurid amphisbaenians.
Digestive anatomy of Halella azteca (Crustacea, Amphipoda)
Authors: Schmitz Eugene H. , Scherrey Patricia M.
Published: February 2005

The digestive tract of the freshwater amphipod Hyalella azteca is a straight but differentiated tube consisting of foregut, midgut, and hindgut divisions. The foregut is subdivided into a tubular esophagus, a cardiac stomach, and a pyloric stomach. The cuticular lining of the cardiac stomach is elaborated into a set of food‐crushing plates and ossicles, the gastric mill, while the pyloric cuticle forms a complex straining and pressing mechanism. Nine caeca arise from the midgut, seven anteriorly and two posteriorly. Four of the anterior caeca, the hepatopancreatic caeca, are believed to be the primary sites of digestion and absorption. The remaining caeca may be absorptive, secretory, or both. The much‐folded hindgut wall is capable of great distention by extrinsic muscle action for water intake to aid in flushing fecal material out of the anus; such action also may stimulate antiperistalsis by intrinsic rectal muscles.
The mechanism of forearm rotation in Varanus exanthematicus
Authors: Landsmeer Johan M. F.
Published: February 2005

In the sprawling gait of Varanus exanthematicus, the bicondylar distal humerus requires both the radius and ulna to rotate in the same direction. The joints between the radius and radiale and between the ulna and ulnare and pisiform accomodate these specific rotations. A ligament system between radius, ulna, radiale, and ulnare causes the radius and ulna to approximate one another during external rotation of the forearm. This approximation is conveyed distally resulting in a narrowing of the hand during external rotation of radius and ulna or during pronation of the free hand. The significance of these and related linkages is discussed.
Seasonal changes in the ultrastructure of the kidney collecting tubule in the lizard Podarcis ( = Lacerta) taurica
Authors: Gabri M. S.
Published: February 2005

In female Podarcis taurica the kidney collecting tubule always consists entirely of mucous‐secreting cells. In males it has a seasonally variable sexual segment and a non variable mucous‐secreting segment. In April the sexual segment is composed of columnar cells with cytoplasm rich in ribosomes and Golgi bodies and apical clusters of large vesicles with fibrous contents. The terminal region of the sexual segment also has pillar‐shaped cells resembling those of the mucous‐secreting segment. By May the accumulation of apical vesicles reaches a maximum, and many cells have apparently extruded their secretion into the lumen. In July all the cells are pillar shaped with dilated endoplasmic reticulum but with few apical vesicles. In September the sexual segment has some cells resembling those of the mucous‐secreting segment and others the sexual segment pillar cells in April. It is suggested that during sexual activity in the spring the sexual segment secretes a spermatozoon‐nutrient protein but subsequently reverts to mucous secretion. The non variable mucous‐secreting regions in both males and females consist of mucous, intermediate, and dark cells. Mucous cells have apical masses of closely packed droplets, whereas dark cells have dense cytoplasm and small, loosely associated apical vesicles. Intermediate cells have some dark cell features but mucous cell apical vesicles. The dark, intermediate, and mucous cells probably represent activity states of a single type. The mucous secretion is interpreted as a protective material which lines the urinary passage and coats the secreted solid urates. Elaborated intercellular spaces in the mucous‐secreting regions may indicate a water absorption capacity in urine concentration.
The functional anatomy of the shoulder of the savannah monitor lizard (Varanus exanthematicus)
Authors: Jenkins Farish A. , Goslow G. E.
Published: February 2005

The excursions of the scapulocoracoid and forelimb and the activity of 18 shoulder muscles were studied by simultaneous cineradiography and electromyography in Savannah Monitor lizards (Varanus exanthematicus) walking on a treadmill at speeds of 0.7–1.1 km/hour. During the propulsive phase, the humerus moves anteroposteriorly 40–55° and rotates a total of 30–40°. Simultaneously, the coracoid translates posteriorly along the tongue‐and‐groove coracosternal joint by a distance equivalent to about 40% the length of the coracoid.

Biceps brachii, coraco‐brachialis brevis and longus, the middle and posterior parts of the latissimus dorsi and pectoralis, serratus anterior, serratus anterior superficialis, subscapularis, supracoracoideus, and triceps usually become active during the late swing phase and continue activity throughout most or all of propulsion. The anterior part of the latissimus dorsi is active during the transition from propulsive to swing phases. Brachialis, deltoideus scapularis, levator scapulae, the anterior part of pectoralis, scapulo‐humeralis posterior, and subcoracoideus are active primarily during the swing phase; they are occasionally active during propulsion. Deltoideus clavicularis, scapulo‐humeralis posterior, sternocoracoideus, and the posterior part of the trapezius are biphasic, with activity in both the propulsive and swing phases.

A number of shoulder muscles in Varanus exanthematicus and Didelphis virginiana (the Virginia opossum) are similar in attachments, in activity patterns with respect to phases of the step cycle, and in apparent actions. These similarities are interpreted as a pattern inherited from the ancestors of higher tetrapods. The sliding coracosternal joint permits an increase in step length without demanding greater excursion at the shoulder and elbow joints.
Corneal morphogenesis in the Indian garden lizard, Calotes versicolor (agamidae)
Authors: Shinde S. L. , Goel Suresh C.
Published: February 2005

The present study traces corneal morphogenesis in a reptile, the lizard Calotes versicolor, from the lens placode stage (stage 24) until hatching (stage 42), and in the adult. The corneal epithelium separates from the lens placode as a double layer of peridermal and basal cells and remains bilayered throughout development and in the adult. Between stages 32– and 33+, the corneal epithelium is apposed to the lens, and limbic mesodermal cells migrate between the basement membrane of the epithelium and the lens capsule to form a monolayered corneal endothelium. Soon thereafter a matrix of amorphous ground substance and fine collagen fibrils, the presumptive stroma, is seen between the epithelium and the endothelium. Just before stage 34 a new set of limbic mesodermal cells, the keratocytes, migrate into the presumptive stroma. Migrating limbic mesodermal cells, both endothelial cells and keratocytes, use the basement membrane of the epithelium as substratum. Keratocytes may form up to six cell layers at stage 37, but in the adult stroma they form only one or two cell layers. The keratocytes sysnthesize collagen, which aggregates as fibrils and fibers organized in lamellae. The lamellae become condensed as dense collagen layers subepithelially or become compactly organized into a feltwork structure in the rest of the stroma. The basement membrane of the endothelium is always thin. Thickness of the entire cornea increases up to stage 38 and decreases thereafter until stage 41. In the adult the cornea is again nearly as thick as at stage 38.
Aspects of masticatory form and function in common tree shrews, Tupaia glis
Authors: Fish Dale R.
Published: February 2005

Tree shrews have relatively primitive tribosphenic molars that are apparently similar to those of basal eutherians; thus, these animals have been used as a model to describe mastication in early mammals. In this study the gross morphology of the bony skull, joints, dentition, and muscles of mastication are related to potential jaw movements and cuspal relationships. Potential for complex mandibular movements is indicated by a mobile mandibular symphysis, shallow mandibular fossa that is large compared to its resident condyle, and relatively loose temporomandibular joint ligaments. Abrasive tooth wear is noticeable, and is most marked at the first molars and buccal aspects of the upper cheek teeth distal to P2. Muscle morphology is basically similar to that previously described for Tupaia minor and Ptilocercus lowii. However, in T. glis, an intraorbital part of deep temporalis has the potential for inducing lingual translation of its dentary, and the large medial pterygoid has extended its origin anteriorly to the floor of the orbit, which would enhance protrusion. The importance of the tongue and hyoid muscles during mastication is suggested by broadly expanded anterior bellies of digastrics, which may assist mylohyoids in tensing the floor of the mouth during forceful tongue actions, and by preliminary electromyography, which suggests that masticatory muscles alone cannot fully account for jaw movements in this species.