The histology,histochemistry and ultrastructure of the cement apparatus of three adult sessile barnacles,Elminius modestus,Balanus balanoides and Balanus hameri

The histology, histochemistry and ultrastructure of the cement gland cells of 3 species of sessile barnacles are described. Cells of both Elminius modestus Darwin and Balanus balanoides (L.) (membranous bases) are similar histologically and ultrastructurally, and within the cells there are 2 distinct regions. One is the site of secretion accumulation, the other the site of secretion synthesis. In Balanus hameri Ascanius (calcareous base) the cells are different in that the cytoplasm is more homogeneous. In all 3 species protein is the final secretion product (cement) of the cement cells. The mode of discharge of secretion from the cells differs between the membrane based and calcareous based barnacles. In the former, there is a series of collecting canals within the cytoplasm of the cement cells (intracellular canals) which join with the larger extracellular cement ducts. Secretion passes into the intracellular canals and is moved along to the larger cement ducts, which have an inner chitin lining. In Balanus hameri (calcareous base) there are no intracellular collecting canals. Secretions are thought to pass from the cement cells into the cement duct cells direct. The cement ducts in this species are not chitin lined.     

Marine Gammaridea (Crustacea: Amphipoda) from the Indian region. Family Ampithoidae

This paper deals with 6 species of marine gammaridean amphipods belonging to the family Ampithoidae. The specimens described were collected from Mandapam (Gulf of Mannar), India and Thankasserry (Quilon, Kerala), India. The collection includes 3 new species, namely Ampithoe (Ampithoe) serraticauda, Ampithoe (Pleonexes) auriculata and Cymadusa imbroglio. Ampithoe (Ampithoe) kergueleni Stebbing (1888) is a new record for this region, while Ampithoe (Ampithoe) ramondi Audouin (1826) and Cymadusa filosa Savigny (1816), the two well-known tropicopolitan members, are briefly redescribed. The study supports Barnard's (1970, p. 23) contention that the genus Pleonexes Bate (1857) (since reduced to subgeneric status under the genus Ampithoe Leach, 1814) represents only a grade of evolution, but suggests that the structure of the 1st maxillary and mandibular palps and the outer lobes of the lower lip should also be taken into consideration, in combination with the telsonic processes, for distinguishing Pleonexes from Ampithoe. Based on this concept, a reappraisal of some of the species of the genera is suggested. The subgenus Ampithoe is created to hold those species of Ampithoe showing typical characteristics of the genus.     

A stereoscan electron microscope study of male reproductive characters in the Jaera albifrons group of species (Crustacea: Isopoda)

The male secondary sex characters of Jaera albifrons Leach, Jaera ischiosetosa Forsman, Jaera praehirsuta Forsman and Jaera forsmani Bocquet are described with the Stereoscan electron microscope (S.E.M.). These characters, which are present on the peraeopods, are the only means of identification for these Jaera species which together form the Jaera albifrons group (Isopoda, Asellota). The male praeoperculum (modified, fused, first pair of pleopods) and appendix masculinae (modified endites of the second pair of pleopods) have also been studied with the S.E.M. and possible functions of the various sex characters are discussed. Both the male operculum and appendix masculinae are similar for each species, suggesting that copulation with females of a different species is anatomically possible. The fact that hybrids are rarely collected in ecological investigations is discussed with reference to the present known information. Two methods of copulation for the members of this group have been proposed and these are discussed. A method of sperm transfer along the male operculum is outlined.     

Morphologie,Entwicklung und Ökologie digener Trematoden-Larven der StrandschneckeLittorina littorea

More than 6000 individuals of the snailLittorina littorea L., from 6 different localities on the coast of the German Bay (North Sea), were examined for larval trematodes by crushing their shells, an additional 6000 by isolation in small quantities of sea water. Six species of larval trematodes were found inL. littorea and described: Notocotylid larva —Cercaria lebouri Stunkard, 1932; Cercaria ofHimasthla elongata (Mehlis, 1831); Cercaria ofPodocotyle atomon (Rudolphi, 1802); Cercaria ofRenicola roscovita (Stunkard, 1932) n. comb.; Metacercaria ofMicrophallus pygmaeus (Levinsen, 1881); Cercaria ofCryptocotyle lingua (Creplin, 1825). Considering the large number of investigated snails, the trematode fauna ofL. littorea in this area is assumed to be completely known. The life cycles ofHimasthla elongata andRenicola roscovita are described. Larvae of the different trematode species show differential preferences for distinct size groups of snail hosts. Juvenile snails are not infected. No correlation exists between infection rates and sex of the hosts. Quantitative aspects of multiple infections are calculated and discussed. The incidence of larval trematodes in the investigated localities differs. Information is presented on seasonal variations of infestations and their possible causes.     

Differing patterns of sequestration of iridoid glycosides in the Mecininae (Coleoptera, Curculionidae)

We analyzed several species of the weevil family Mecininae (Coleoptera, Curculionidae) that all feed on iridoid glycoside (IG) containing plants of the Plantaginaceae to investigate whether the beetles sequester these deterrent substances from their host plants. Within the Mecininae two genera of the tribe Cionini were found to sequester aucubin and catalpol: Cionus Clairville and Schellenberg and Cleopus Dejean. Both analyzed genera of the Mecinini, Mecinus Germar and Rhinusa Stephens, do not sequester IGs although the compounds are present in their food plants. They thus represent the first case of specialists on IG plants that have not evolved adaptations to use the compounds. However, in contrast to the Cionini these genera have a hidden lifestyle, so that their need for defence might be lower. Both Cionus and Cleopus, sequester catalpol with a higher efficiency than aucubin. However, in contrast to Cionus species, Cleopus species only sequester catalpol. In species feeding on Scrophularia, the aucubin concentration is higher while in beetles on Verbascum catalpol is usually dominating. This pattern can also be detected in the only species living on both plants, Cionus hortulanus. The ability to sequester IGs must have a single origin at the base of the sister genera Cionus and Cleopus.     

The life cycle ofClytia attenuata (calyptoblastea: Campanulariidae)

The life cycle of the hydroidClytia attenuata (Calkins) (Calyptoblastea: Campanulariidae) has been completed in the laboratory including development of the medusa, previously described asPhialidium lomae Torrey (Leptomedusae: Campanulariidae). Under laboratory conditions, the hydroid exhibits some morphological variation. Characteristic branching of the hydroid occurs at temperatures between 17° to 19°C. At 13° to 15°C the colonies are unbranched and cannot be distinguished fromClytia cylindrica L. Agassiz. Young medusae are similar to other young species ofPhialidium. Development to the adult form requires 25 to 30 days at 17° to 24°C. The adult medusae are 6 to 10 mm in diameter, watch-glass shaped, and have 20 to 28 tentacles. Based on the adult medusa,Clytia attenuata is maintained as a valid species.     

The structure of the latero-frontal cirri on the gills of certain lamellibranch molluscs and their role in suspension feeding

Photomicroscopy and scanning electron microscopy were used to determine the fine structure of the latero-frontal cirri on the gills of three species of bivalve mollusc: Mytilus edulis Linn., Barnea candida (Linn.), and Petricola pholadiformis Lam. The component cilia are seen to branch off alternately along the length of each cirrus. Each of these free, lateral lengths of the cilia are separated from the next on their side by a mean distance of 0.6 m. They extend to a mean length of 2.7 m in M. edulis, the species described in detail. It is shown that a complete straining mesh can be formed over the gill ostium during normal filtering and the aperture of this mesh correlates well with the previously recorded filtering efficiency for Mytilus.     

Follicovitellosum indicum,a new trematode,found in the fish Belone belone

A new trematode, collected in 1971 from Ratnagiri, India, is described as Follicovitellosum indicum sp. nov. A new subfamily, Follicovitellotrematinae is created within the family Zoogonidae Odhner, 1911, to receive the new genus Follicovitellosum, with its genotype F. indicum. The new species is characterized by the follicularized nature of its ovary; the ovarian follicles are posttesticular. The vitellarium is further divided into several follicles which are largely in the pre-ovarian zone, but post-acetabular and posttesticular in location.     

Fungi from the Sargasso Sea

Fungi inhabiting Sargassum spp. from the Sargasso Sea were examined. Three ascomycetes were found, two of which are new records for this environment. Haloguignardia oceanica (Ferdinandsen et Winge) Kohlm. comb. nov. was collected only once before, over 50 years ago. Haloguignardia tumefaciens (Cribb et Herbert) Cribb et Cribb was known only from Australia and New Zealand. Imperfect states of these ascomycetes and fruiting bodies (acervuli) of a hyperparasitic deuteromycete (cf. Sphaceloma sp.) were found for the first time in the galls of the two species. Lindra thalassiae Orpurt et al., previously known only from the sea grass Thalassia testudinum Köngig, develops in air bladders of Sargassum sp., causing a shedding of infested vesicles. Possible reasons for the rarity of fungal species and diseased plants in the Sargasso Sea are diseussed.Dedicated respectfully to my teacher, Professor Dr. H Drawert (Universität Famburg), on the occasion of his 60th birthday.     

Glycohistochemistry of a marine sponge, Chondrilla nucula (Porifera, Desmospongiae), with remarks on a possibly related antimicrobial defense strategy and a note on exopinacoderm function

Based on carbohydrate histochemistry, including the use of lectins, and TEM, the study describes the distribution of terminal sugars in different structures of the demosponge Chondrilla nucula. The results of the general and specific carbohydrate histochemical approaches confirmed the presence of acidic and neutral glycoconjugates in the cells, and, with declining amounts from the ectosome to the mesohyl, in the extracellular matrix (ECM). AB-PAS staining indicated acidic complex carbohydrates particularly in the exopinacoderm, and more neutral ones in the cells and the ECM of the mesohyl. The PO-lectins applied demonstrated a general spectrum of free saccharide residues (α-d-mannose, α-/β-d-N-acetylglucosamine, α-d-N-acetylgalactosamine, α-d-galactose, β-d-galactose) in both sponge parts; α-l-fucose was only distinct in the ectosome. Sialic acids [siaα(2,3)-galactose, siaα(2,6)-N-acetylgalactosamine] were dominant in the very thin exopinacoderm, indicating O-linked high molecular weight glycoproteins. In this way a glycophysiologically ‘rigid’ outer mucus cover is developed as protection against mechanical hazards. Some of the free sugars (α-d-mannose, N-acetylglucosamine, N-acetylgalactosamine β-d-galactose, α-l-fucose) are known to prevent the adherence of different bacteria and fungi to cellular surfaces. Thus a high concentration of such sugars, may impede massive attacks of micro-inhabitants on mobile sponge cells, pinacocytes, and the exopinacoderm layer.     

The chromosomes of Trypetesa lampas (Cirripedia,Acrothoracica)

Observations were made of the chromosomes of the burrowing barnacle Trypetesa lampas (Hancock). A method of squash preparation was used, which incorporated staining the material in a solution of 2% orcein in 45% acetic acid. The diploid number of chromosomes of T. lampas was found to be 12 and the haploid number 6, in both males and females. No obvious chromosomal mechanism of sex determination was found. There was, therefore, no cytogenetic confirmation of Kühnert's view (1934) that the sex of the larva is predetermined genetically. During mitosis in the females and embryos of Trypetesa lateralis Tomlinson and Kochlorine floridana Wells and Tomlinson, the diploid number of chromosomes was found to be about 14. The numbers of chromosomes in the 3 species of Acrothoracica studied were approximately half those observed in all 12 species of Thoracica and all 5 species of Rhizocephala previously investigated.     

Effect of food location and quality on recruitment sounds and success in two stingless bees,<Emphasis Type="Italic"> Melipona mandacaia</Emphasis> and<Emphasis Type="Italic"> Melipona bicolor</Emphasis>

It is unclear whether stingless bees in the genus Melipona (Hymenoptera, Apidae, Meliponini) can reliably encode the distance to a food source through recruitment sounds produced inside the nest, in part because the sound features correlated with distance also vary with food quality. We therefore trained marked foragers of two species, Melipona mandacaia and M. bicolor, to feeders at different distances and to different sucrose concentrations at the same distance. In both species, foragers successfully recruited to a rich 2.5-m food source and produced pulsed recruitment sounds in which pulse duration was significantly and positively correlated with distance to the rich food source. When returning from poorer food sources (0.6–1.5 m), foragers of both species decreased sound production, producing shorter sound pulses and longer sound interpulses than they did for 2.5 m food located at the same distance. Thus the temporal structure of M. mandacaia and M. bicolor recruitment sounds varies with distance and food quality. However, nestmates were not recruited by performances for poorer food sources (0.6–1.5 m), whose sucrose concentration was sufficiently low to affect recruitment sounds. Surprisingly, the interphase (the time between behavioral phases that communicate location) also increases with decreasing food quality in the closely related honeybees (Apis), suggesting a potential homology in the effect of food quality on the recruitment systems of Apis and Melipona. We explore the evolutionary implications of these similarities.Communicated by M. Giurfa     

Larval development of the spider crab Pisoides edwardsi (Decapoda,Brachyura) under laboratory conditions

Larvae of Pisoides edwardsi (Bell, 1835) have been reared in the laboratory at 2 different temperatures (13.8° and 18.5°C), from hatching to megalops stage. The two zoeal stages and the megalops, as well as the setation of the functional appendages are described and illustrated. The main characteristics useful to differentiate the larvae of P. edwardsi from those of Libidoclaea granaria, the other Chilean species belonging to the same sub-family, are discussed. Data on duration of zoeal development, length of moulting intervals, and mortality at the 2 test temperatures, are also given.This study was financially supported, in part, by the Chilean Ministry of Agriculture.     

The mouthparts of the members of the Jaera albifrons group of species (Crustacea: Isopoda)

The mouthparts of Jaera albifrons Leach, Jaera ischiosetosa Forsman, Jaera praehirsuta Forsman and Jaera forsmani Bocquet were examined with the light microscope and the Stereoscan electron microscope, and were found to be identical in all species. The structure of the mouthparts indicate that all four species feed by scouring and abrading algal or bacterial films from rocks or Fucus. Food, therefore, does not seem to be an isolating factor involved in the microdistribution of the four species on a shore.     

Temperature tolerance of the polychaete worms Diopatra cuprea and Clymenella torquata

The resistance to high temperatures of two species of intertidal tube-dwelling polychaete worms has been tested to show seasonal and geographic variations. The summer 50% survival temperature at Beaufort, North Carolina, was 42.5 °C for Diopatra cuprea (Bosc) and 40.5 °C for Clymenella torquata (Leidy). Winter 50% survival temperatures for both species at Beaufort were approximately 4.0 C° lower. Both species showed a geographic difference in 50% survival temperature of more than 4.0 C° between North Carolina and Massachusetts in summer. D. cuprea from the Mississippi coast showed a lower survival temperature, probably due to combined temperature and salinity effects. Laboratory acclimation of C. torquata from Beaufort at low temperatures, during summer months, produced experimental results similar to those from winter animals. The seasonal differences in temperature tolerance are phenotypic expressions of a physiological response which can be related to environmental temperature patterns.     

Effect of low dissolved oxygen concentrations on the ventilation rhythm of three tubicolous crustaceans,with special reference to the phenomenon of intermittent ventilation

The pleopod ventilatory activity of the tube-dwelling amphipods Corophium volutator (Pallas) and C. arenarium Crawford is intermittent. Unlike the free-living amphipod Marinogammarus obtusatus (Dahl), which increases its rate of pleopod beating, the pleopod beat rate of both Corophium species is unaffected by low oxygen concentrations. However, the nature of the intermittent ventilation rhythm is altered so that, at low oxygen concentrations, the pleopods of Corophium beat almost continuously. It is suggested that the intermittent ventilation of Corophium can be interpreted as an adaptation to a tubicolous existence. The peracaridean Tanais chevreuxi Dollfus has 2 independent ventilatory systems, the maxilliped epipodites and the pleopods. The former, which respond to low oxygen concentrations, are thought to be the principal respiratory organs of T. chevreuxi, while the pleopods, which show no response to low oxygen tensions, are believed to be primarily concerned in filter feeding.     

Larval development of the red crab Pleuroncodes monodon (Decapoda Anomura: Galatheidae) under laboratory conditions

Larvae of Pleuroncodes monodon (Milne-Edwards, 1837), a red crab of commercial importance in South America, were reared in the laboratory at 2 different temperatures (15° and 20°C), from hatching up to the last larval stage. The 5 typical stages, with their corresponding functional appendages, are described and figured. The main characteristics useful in differentiating larvae of P. monodon from those of the other Chilean species of Galatheidae and its northern congener P. planipes are discussed. Data on duration of each larval stage, length of moulting intervals and mortality at the 2 test temperatures are also given.This study was financially supported by the Chilean Ministry of Agriculture and by the National Commission for Scientific and Technological Research (CONICYT).     

Electrophoretic studies of serum proteins of four Tilapia species (Pisces)

The blood serum of 4 Tilapia species were analyzed electrophoretically for protein components, and the percentage of proteins in each fraction was determined. Sera from Tilapia nilotica Linnaeus, T. zillii Gervais, T. galilaea Artedi, and T. aurea (Steindachner) were studied. Characteristic protein fractions for each species were obtained. The species differed in the number of protein fractions and in the final mobilities; T. nilotica sera migrate 120 mm, T. zillii sera 95 mm, T. galilaea sera 90 mm, and T. aurea sera 118 mm. The mobilities for fractions 1 and 2 were similar for the 4 species' sera. Inter-specific differences in the amount of protein occurred. Diet may be a major contributing factor to the variations observed in the amount of total protein.     

Desiccation as a factor in the intertidal zonation of barnacles

Four species of balanomorph barnacles, Balanus crenatus Brugière, B. balanoides (L.), Elminius modestus Darwin and Chthamalus stellatus (Poli), were studied to assess the susceptibility of intertidal barnacle species to desiccation. Known sized samples of barnacles were exposed to controlled desiccating conditions and subsequent survival and water loss were determined. It is clear that the ability to live high on the shore is dependent on a reduction of the overall permeability to water loss. Because of greater surface area to volume ratios, small stages are particularly prone to desiccation. In normal intertidal emersion periods, small stages of B. crenatus particularly, and also of B. balanoides and E. modestus which are similar in their desiccation resistance, would be susceptible to desiccation at normal temperatures and low humidities. Large barnacles would be more prone to death from high temperatures when the tide is out. The spat of C. stellatus, although surviving much longer than spat of larger dimensions of the other species, must also be prone to prolonged emersion conditions at high shore levels.     

Dispersal of phytoplanktotrophic shipworm larvae (Bivalvia: Teredinidae) over long distances by ocean currents

Shipworms or Teredinidae may be dispersed either as adults in floating wooden objects or as pelagic larvae drifting near the sea surface. Five shipworm species, i.e., half of those having an amphi-Atlantic geographical distribution, are known also to have pelagic phytoplanktotrophic larvae which can be carried by ocean currents. From a series of 742 plankton samples taken from throughout the temperate and tropical North Atlantic Ocean, it can be shown that shipworm larvae are not uncommon in the open sea. Teredinid veligers were found in 19% of all samples taken. One species of larvae, identical in all details to that described by Rancurel (1965), is particularly prevalent and is tentatively identified as Teredora malleolus (Turton). A definitive identification will be possible only after the pelagic larvae of the other Atlantic species are known. The larvae of Teredora malleolus are found throughout the North Atlantic Gyre and the adjacent temperate and tropical seas, and from scattered records in the South Equatorial Current. Larvae of other unidentified Teredinidae species were also found. The distance that larvae may be transported depends upon the length of pelagic larval development and the velocity of the currents. From the known current velocities it can be shown that, even in a few weeks, larvae may be dispersed many hundreds of kilometers. The geographical distribution of shipworm larvae suggests that they are carried along the coasts of continents and even across ocean basins, and that this dispersal must be an important factor in the geographical distribution of the adult forms and in the maintenance of genetic continuity between populations otherwise isolated from one another.Contribution No. 2555 from the Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA