A New Genus and Species of the Family Anulidentaliidae (Scaphopoda: Dentaliida) and its Systematic Implications

Shell, radula, and anatomy of Epirhabdoides ivanovi new genusand species are described from a sample of the Russian VitjazExpedition from the Japan Trench. It is distinguished from thesimilar Laevidentalium sominium by shell morphometrics and radulamorphology. The radula is almost identical with that of Anulidentaliumbambusa (Anulidentaliidae). The anatomy of the mantle margins,however, including dorsolateral slits at the anterior mantlemargin and a connective tissue bolster at the posterior mantleopening is that of the family Rhabdidae. In a parsimony analysisEpirhabdoides ivanovi takes an intermediate position betweena basal grade of Gadilinidae and the remaining Dentaliida implyingconvergent evolution of mantle characters. An alternative butless parsimonious tree with E. ivanovi as sister taxon to Rhabdusrequires convergences in radula characters. This is the firstdocumented case of convergent anatomical features among Scaphopodaand enhances the need of radula and soft part investigationof the conchologically little informative, smooth-shelled dentaliidgroups. (Received 16 March 1998; accepted 1 June 1998)     

Morphology of the anterior digestive system of tonnoideans (Gastropoda: Caenogastropoda) with an emphasis on the foregut glands

ABSTRACT

Tonnoideans are marine carnivorous caenogastropods that prey on different invertebrates, namely polychaetes, sipunculids, bivalve and gastropod molluscs, and echinoderms. The morphology of the digestive system of 20 species from five families of the Tonnoidea was examined (for most of these species for the first time), and the salivary glands of six of them were studied using serial histological sections. Most of the studied families are rather similar anatomically, except Personidae (Distorsio), which differs both in proboscis morphology and the structure of the salivary glands. In most tonnoideans the salivary glands are split morphologically and functionally into anterior and posterior lobes, the latter synthesising strong sulfuric acid. The ducts of the posterior lobes are lined with non-ciliated epithelium and receive usually paired ciliated ducts from the anterior lobes to form a non-ciliated common duct, opening into the buccal cavity. In Personidae, the salivary glands are not separated into lobes, but are instead composed of ramifying tubules that are histologically different in the proximal and distal parts. Radulae of Tonnoidea are rather variable, with different patterns of interlocking teeth, both in the transverse and longitudinal rows, which may be related to particular feeding mechanisms. Due to the peculiarities of Personidae, the close relationship between that family and the rest of the Tonnoidea is questioned.     

吴氏角叶蚤幼虫形态记述及其与同属另外三种的比较（蚤目：角叶蚤科）

描述了吴氏角叶蚤Ceratophyllus wui Wang et Liu 的幼虫形态,并与同属三种蚤幼虫作比较,标本采自湖北省西北部神农架海拔2 300 m 短嘴金丝燕四川亚种 Collocalia brevirostris innominata巢窝内。     

DISTRIBUTION OF BIOGENIC AMINES AND RELATED ENZYMES IN THE RAT PITUITARY GLAND

Abstract— Biogenic amines and related enzymes were quantitatively measured in the pituitary gland of the rat. The sensitivity of the assays used allows the determinations to be performed in single pituitary lobes. Relatively high values of histamine and serotonin were found in all three lobes, with higher amounts in the posterior and intermediate lobes. Highest catecholamine concentrations were detected in the posterior lobe, and only very low amounts of dopamine were measured in the anterior lobe. Throughout the gland, norepinephrine concentrations were low, about one-tenth that of dopamine. Tryptamine could not be detected. High levels of A and B monoamine oxidase were found in all three pituitary lobes. Tyrosine hydroxylase activity was measured in the posterior and intermediate lobes, but was not detected in the anterior lobe. Tryptophan hydroxylase was present in all three pituitary lobes. A relatively low catechol- O -methyltransferase activity was found in the anterior lobe, and none was detected in the intermediate and posterior lobe. Choline acetyltransferase, dopamine-β-hydroxylase and phenylethanolamine- N -methyltransferase activities could not be detected.     

The central nervous control of the adductor behaviour of lamellibranch molluscs.

In Egeria radiata (L.) and Mutela dubia (Gmelin) decerebration does not result in tonus of the posterior adductor muscle and each species continues to exhibit its characteristic rapid and slow rhythms. Excitatory and inhibitory nerve pathways originating in the cerebral ganglia terminate on the visceral ganglia. The cerebral ganglia alone do not exhibit any rhythm; the anterior adductor muscle remains relaxed after excision of the visceral ganglia. The mid-dorsal and the anterior lobes of the visceral ganglia in Scrobicularia plana (Da Costa) control all adductor activity. Groups of potentials in the posterior adductor nerves originate from the different lobes and are separate physiological mechanisms.     

Possible Boring Structures of Sipunculids

At the present time there is no experimental evidence whichlinks the supposed boring activities of sipunculids to a specificorgan or structure. Structures which have been speculativelyassociated in the literature with boring are: hooks and spinesof the introvert, cuticular papillae with associated epidermalglands, anterior and posterior horny shields, and anterior calcareousshields. In this review these structures are described as theyoccur in five representative species of sipunculids collectedby the author from calcareous rock in the Indian Ocean or theCaribbean Sea. The five species are: Pliascolosoma antillarumGrube and Oersted, Phascolosoma dentigerum (Selenka and de Man), Paraspidosiphon steenstrupi (Diesing), Lithacrosiphon gurjanovaeMurina, and Cloeosiphon aspergillum (Quatrefages). Localitiesof collections are cited, habitats and burrows are described,and the behavior of the animals as observed in the field andlaboratory is noted. In view of the morphology of the possibleboring structures and in light of observations on habitats andbehavior, the possible roles of the structures in boring activitiesare discussed. Highly organized horny shields are present at the anterior andposterior extremities of thetrunk or Paraspidosiphon steenstrupi,whereas anterior calcareous shields are characteristic of Cloeosiphonaspergillum and Lithacrosiphon gurjanovae. Papillae and epidermalglands are present in all five of the species but these aremost highly developed in Phascolosoma dentigerum and P. antillarum.Of the species considered, only P. antillarum lacks hooks onthe introvert. Because of the position of the animal within the rock with anteriorend directed toward themouth of the burrow, it is assumed thatthe anterior shields and the hooks of the introvert play nosignificant role in the formation of the burrow. However, therigid papillae of the trunk and the thickened posterior shield,if rubbed against the wall of the burrow, presumably could beutilized in the mechanical attrition of the more friable rock,whereas the secretory products of the numerous epidermal glandsmight be implicated in the chemical dissolution of the hardersubstrates.     

THE ANATOMY AND RELATIONSHIPS OF ELACHISINA DALL (GASTROPODA: RISSOACEA)

Species of Elachisina are marine and extend from the Caribbeanand western North and Central America to the Philippines, Hawaiiand New Zealand. The anatomy and other morphological featuresof Elachisina ( = Microdocluis) floridana (Rehder) from theFlorida Keys are described and compared with rissoacean familiesjudged to be most closely allied. This species has a uniquecombination of characters which do not correspond to those character-setsused to define any known rissoacean family. Important featuresinclude a metapodial as well as pallial tentacles, a wide ctenidiumwith low, triangular filaments, an osphradium which is shortrelative to the ctenidium, an S-shaped loop of the intestinewhich extends into the pallial roof, long dorsal folds in themidoesophagus, a rather loosely organised nervous system, anopen prostate gland from which the pallial vas deferens exitsat its anterior extremity, glandular lobes on the penis, a non-glandularfold on the right side of the ventral channel of the capsulegland and a fold on the left side in the posterior end of thechannel, a pair of seminal receptacles lying between the albumenand capsule glands, a bursa which lies alongside the capsulegland and opens posteriorly to the ventral channel and a U-shaped,expanded section of the oviduct proximal to the albumen glandand seminal receptacles. This combination of characters is consideredto be sufficiently distinct to arrant the erection of a newfamily-level taxon to accommodate the small group of speciesjudged to be congeneric with E. floridana. The Elachisinidaeappears to be most closely related to the Rissoidae, Iravadiidaeand Hydrobiidae. (Received 19 October 1983;     

Biochemical compartmentation of fish tissues: chronic toxicity of mercuric nitrate on visceral phosphomonoesterases in Channa punctatus (Bloch)

Effect of sub-lethal dose of mercuric nitrate was studied in anterior, middle and posterior regions of kidney, anterior and posterior regions of left and right liver lobes, cephalic, thoracic and caudal regions of muscle and left and right gill tissues of C. punctatus in relation to acid and alkaline phosphatase under chronic studies. Middle region of kidney registered maximum rise and fall of acid and alkaline phosphatase, respectively. Right lobe of liver showed more rise and fall of acid and alkaline phosphatase activity respectively. Similarly, left gill is more pronounced than the right one. The observed enzymatic variations were discussed in relation to the biochemical constituents and physiological coordination rendered by these tissues.     

Chemical Defence in Cephalaspidean Gastropods: Origin, Anatomical Location and Ecological Roles

Within the opisthobranchs, the cephalaspideans are traditionallyconsidered a transitional group between typical testacean prosobranchsand shell-less opisthobranchs. The cephalaspidean anatomy, includingthe presence of a cephalic shield, is related to burrowing throughsoft sediment. Recent studies have shown that some herbivorousand carnivorous cephalaspideans contain secondary metabolites.The micro-herbivorous bubble snails of the Bullidae and Haminoeidaefamilies are known to have secondary metabolites which have differentecological roles. The polypropionates isolated from Bulla gouldianaand B. striata were deterrent to fishes while the secondarymetabolites of Haminoea callidegenita, H. fusari, H. hydatis,H. navicula, H. orbignyana and H. orteai were alarm pheromonesemployed during cross copulation. In Bulla gouldiana and B.striata, the defensive secretion was located mainly in a whitegland along the margin of the mantle. In Haminoea species, alarmpheromones were located in external parts (cephalic shield,parapodial lobes and posterior pallial lobe). The carnivorous cephalaspideans Navanax inermis and Philinopsisdepicta employ chemotaxis to follow the slime trail of theirprey, which include other cephalaspideans or even congenericindividuals. N. inermis and P. depicta sequester alarm pheromonesand allomones from their cephalaspidean prey, which are ejectedwhen N. inermis and P. depicta are disturbed. The specific metabolic patterns of Mediterranean cephalaspideanssuggest that these patterns can be used as chemotaxonomic markers.We propose the use of a single Thin Layer Chromatography todifferentiate among Mediterranean Haminoea species. (Received 3 February 1997; accepted 22 May 1998)     

The brain structure of selected trypanorhynch tapeworms

The brain architecture in four species of tapeworms from the order Trypanorhyncha has been studied. In all species, the brain consists of paired anterior and lateral lobes, and an unpaired central lobe. The anterior lobes connect by dorsal and ventral semicircular commissures; the central and lateral lobes connect by a median and an X-shaped crisscross commissure. In the center of the brain, five well-developed compact neuropils are present. The brain occupies a medial position in the scolex pars bothrialis. The ventral excretory vessels are situated outside the lateral lobes of the brain; the dorsal excretory vessels are located inside the brain and dorsal to the median commissure. The brain gives rize four anterior proboscis nerves and four posterior bulbar nerves with myelinated giant axons (GAs). The cell bodies of the GAs are located within the X-commissure and in the bulbar nerves. Highly developed serotonergic neuropils are present in the anterior and lateral lobes; numerous 5-HT neurons are found in the brain lobes including the central unpaired lobe. The X-cross commissure consists of the α-tub-immunoreactive and 5-HT-IR neurites. Eight ultrastructural types of neurons were found in the brain of the three species investigated. In addition, different types of synapses were present in the neuropils. Glial cells ensheath the brain lobes, the neuropils, the GAs, and the bulbar nerves. Glia cell processes form complex branching patterns of thin cytoplasmic sheets sandwiched between adjacent neural processes and filling the space between neurons. Multilayer myelin-like envelopes and a mesaxon-like structure have been found in Trypanorhyncha nervous system. We compared the brain architecture of Trypanorhyncha with that of an early basal cestode taxon, that is, Diphyllobothriidea, and present a hypothesis about the homology of the anterior brain lobes in order Trypanorhyncha; and the lateral lobes and median commissure are homologous brain structures within Eucestoda.     

DISTRIBUTION, HABITAT AND MORPHOLOGY OF THE CARIBBEAN CORAL- AND ROCK-BORING BIVALVE,LITHOPHAGA BISULCATA (d'ORBIGNY) (MYTILIDAE: LITHOPHAGINAE)

Lithophaga bisulcata is the most common Caribbean and Atlanticlithophagine and is the only species of the genus known to occurfrequently in both living and dead coral. The abundance in livingcorals is non-random and variable. Most common hosts are Siderastereasiderea and Stephanocoenia michelini. The bivalves are moreabundant in their preferred hosts than in dead coral. Individualsfrom the two habitats are indistinguishable in shell shape,musculature and size of boring and posterior pallia! glands,indicating a single population. Boreholes differ in the twohabitats with respect to size and lining. Linings are formedat the "inactive" end of the burrow; therefore living coralinhabitants line the anterior end of the burrow and dead coralborers line the posterior end. Recruitment rates are unknownin dead coral but were very low in living coral (Received 9 June 1987;     

Salivary glands in Cicadidae (Hemiptera: Cicadoidea): comparative morphology, ultrastructure, and their phylogenetic significance

The present investigation provides information on gross morphology and ultrastructure of salivary glands of species in Cicadidae in detail. The structure of the salivary glands of 11 representative species from 10 genera belonging to three subfamilies of Cicadidae was studied using light microscopy and transmission electron microscopy. In the examined species, the salivary glands are paired structures, and each of which is comprised of a principal gland (pg) and an accessory gland (ag). The pg is divided into anterior and posterior lobes, and both of which consist of numerous long digitate lobules. The lobules at the base of the long digitate lobules of posterior lobe are greatly short; here, we named as “short lobules.” All the lobules vary in size, disposition, length, and shape. The anterior lobe and posterior lobes are connected by an anterior–posterior duct (apd). Two efferent salivary ducts (esd), derived from corresponding posterior lobes, fuse to form a short common duct which enters into the saliva syringe. The ag is composed of a greatly tortuous and folded accessory salivary tube, a gular gland (gg) constituting of several acini, and an accessory salivary duct (asd). The asd joins the esd at the place where the latter emergences. Constituents and arrangement of the salivary glands, the number and shape of the long digitate lobules in the anterior and posterior lobes, and the visibility of the apd were promising characters for the taxonomic and phylogenetic analysis of Cicadoidea. The variations of secretory granules in size, shape, and electron density in lobule cells of pg of Platypleura kaempferi probably indicating different materials are synthesized. The absence of the infoldings of basal plasma membrane in the basal area of the cells and the presence of electron-lucent vesicles in the cytoplasm of the gg cells of P. kaempferi might suggest that the secretions of gg are more watery.     

High-Protein Carboxymethylase Activity and Low Endogenous Methyl Acceptor Proteins in Posterior Pituitary Lobe of Rats Lacking Neurophysin-Vasopressin (Brattleboro Rats)

Abstract: The activity of protein carboxymethylase and the endogenous protein methyl acceptor capacity were examined in the posterior, intermediate, and anterior lobes of the pituitaries of homozygous Brattleboro rats with diabetes insipidus and in heterozygous Brattleboro and Long-Evans control rats. Protein carboxyl methylation is selectively altered in the posterior pituitary lobes of homozygous Brattleboro rats. Protein carboxymethylase activity is higher (+40%) and endogenous methyl acceptor protein capacity is lower (-80%) with respect to heterozygous Brattleboro and Long-Evans control rats. This latter change is correlated with decreased methylation of proteins of a molecular weight of approximately 11K daltons, is selective for the posterior pituitary lobe, since it does not occur in the intermediate and anterior lobes, and probably reflects the absence of vasopressin-associated neurophysin in homozygous Brattleboro rats. Our results support a physiological role of protein carboxyl methylation in the neurosecretory process in the posterior pituitary gland.     

Preferential posterior cerebellum defect in BETA2/NeuroD1 knockout mice is the result of differential expression of BETA2/NeuroD1 along anterior-posterior axis

BETA2/NeuroD1 has been shown to play a major role in terminal differentiation of the pancreatic and enteroendocrine cells, as well as for the survival of photoreceptors. Here, we report that the loss of BETA2/NeuroD1 affected the cerebellar development with a major reduction of granule cell number. However, there is a differential reduction of granule cells along the anterior and posterior axis of the cerebellum; while the reduction of granule cells in the anterior lobes is substantial, there is an almost complete loss of granule cells in the posterior compartment. To understand the mechanism for this anterior-posterior difference, we carried out detailed analyses. We found that both BETA2/NeuroD1 and its direct target TrkC, expression commence earlier in the posterior part than those in the anterior part during cerebellum development. Consequently, loss of BETA2/NeuroD1 enhances granule cell death in the posterior 2 days earlier than the anterior. Furthermore, the higher rate of cell death in the posterior of the cerebellum is concomitant with the reduction of TrkC expression in knockout mice. Thus, our data indicate that preferential expression of BETA2/NeuroD1 and TrkC in posterior lobes explains the earlier start of cell apoptosis and preferential loss of granule cells in the posterior lobes.     

ULTRASTRUCTURE OF POLAR LOBES IN EGGS OF THE FRESHWATER PROSOBRANCH GASTROPOD AMNICOLA LIMOSA

The structure of polar lobes in eggs of the freshwater prosobranchgastropod Amnicola limosa has been studied by light microscopyand by transmission electron microscopy. A cytoplasmic localization,discovered within the lobes, is described. Its morphology andsubsequent pattern of dispersal are similar to that of the vegetalbody in the polar lobes of Bithynia tentaculata. (Received 12 January 1982;     

Atebbania Bernasconii, a New Genus and Species from Subterranean Waters of the Tiznit Plain, Southern Morocco (Gastropoda: Hydrobiidae)

The new genus Atebbania is described for a new hydrobiid species,A. bernasconii, which lives in groundwaters of southern Morocco.Of the Hydrobiidae genera with known shell and anatomy Moitessieriais the closest to Atebbania. The two share the following characters:shell elongate; teleoconch surface with evident microsculpture;seminal receptacle absent. Atebbania is distinguished from Moitessieriaby: shell ovate; penis with a) apical stylet, b) one lobe bentdownward on left (inner) side and c) penial duct running nearthe right (outer) side; posterior end of foot indented. Atebbaniabernasconii n. sp., lives in a limited area, the Tiznit plainin southern Morocco. Other stygobiont hydrobiids from otherareas of Morocco are currently being studied. None of them appearsto be closely related to A. bernasconii or to the species ofMoitessieria (Received 10 February 1998; accepted 30 April 1998)     

Development of the coelomic cavities in larvae of the living isocrinid sea lily Metacrinus rotundus

Coelomogenesis in the isocrinid sea lily, Metacrinus rotundus, is described through the swimming larval stages. After the late gastrula stage, the archenteron separates from the ectoderm to form an archenteral sac, which develops into a dumbbell shape consisting of anterior and posterior lobes, and a middle part connecting both lobes. The anterior and posterior lobes, and the middle part, become separated into an axo-hydrocoel, the left and right somatocoels and an enteric sac, respectively. The hydrocoel forms from the left lower edge of the axo-hydrocoel and becomes separated from the axocoel by the late dipleurula stage, when chambered organs and coelom X bud off from the anterior tip of the right and left somatocoels, respectively. Coelom X does not occur in comatulid crinoids (feather stars), and its fate is unclear. The pore canal extends from the axocoel. The hydrocoel differentiates into a crescent shape at the overtime semidoliolaria stage, a few days after the semidoliolaria becomes competent to settle. Coelomogenesis in M. rotundus is much simpler than in the comatulids and probably represents the ancestral mode of the crinoids. As each portion of the dumbbell sac differentiates almost in situ into each coelom, presumptive fates in the sac are easily followed in M. rotundus.     

The Roles of Pink and Red Muscle in Powering Steady Swimming in Scup, Stenotomus chrysops

Fishes power steady, undulatory swimming using both red andpink muscle. In this study we examined the roles of the twofiber types in generating power for swimming by using two-steptechnique. First, in vivo data is collected from swimming fish,and second, the electrical activity and muscle length changeconditions recorded in vivo are recreated in vitro with isolatedmuscle bundles. Force production and power generation by muscleduring swimming can then be estimated. In scup, both red andpink muscle are recruited to power swimming at the maximum sustainedswimming speed. For both fiber types, the duration of electricalactivity decreases from anterior to posterior. However, theamplitude of muscle length change increases anterior to posterior.Mass-specific power production increases posteriorly for bothmuscle types. The faster contraction kinetics of pink muscletranslate to higher power production pink muscle relative tored muscle for all longitudinal positions of the fish. Determinationof absolute power production, based on mass-specific power andmuscle mass, shows that the posterior regions of the fish generatethe most power for swimming. At 20°C, red muscle generatesmore absolute power than pink due to its higher muscle mass.However, at 10°C, pink muscle generates more absolute powerthan red, because red muscle produces little or no positivepower for all longitudinal positions.