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.     

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.     

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.     

Hematological studies on some Nile fishes,Tilapia nilotica,Lates niloticus,and Labeo niloticus

Hemoglobin content of 3 Nile fishes — Tilapia nilotica Linnaeus, Lates niloticus Linnaeus and Labeo niloticus Forskal— were examined. Clear differences in hemoglobin and hematocrit values were observed, and seasonal variation in the hemoglobin content of Lates niloticus and Labeo niloticus were noticed. There is a correlation between hematocrit value and hemoglobin content of the 3 species examined. The chloride content is higher in the species with lower hemoglobin content.     

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.     

Petroderma and Porterinema in the New World

Two species of crustose brown algae (Ralfsiaceae) are discussed. Petroderma maculiforme is described from several Massachusetts collections and Porterinema fluviatile is described for the first time from North America. The known world-wide distribution of both species is cited, and data are given on their ecology, and vegetative and reproductive periodicities. The wide range of salinities from which plants of these species have been collected indicate that they are both euryhaline. Lithoderma lignicola Kjeliman (1883) is synonymized with Petroderma maculiforme (Wollny) Kuckuck (1897) and Porterinema marina Jaasund (1965) with. P. fluviatile (Porter) Waern (1952).Systematics-Ecology Program Contribution No. 196.     

A continuous recirculating culture system for planktonic copepods

The calanoid copepods, Acartia clausi Giesbrecht and Acartia tonsa Dana, are maintained at high densities in continuous culture at 15°C. Synthetic sea-water medium is recirculated through filters and a foam tower which limits accumulation of dissolved wastes and various metabolites. The ciliate Euplotes vannus Müller is associated in culture with the copepods, and effectively controls bacterial population and accumulation of algal debris. The copepods graze upon the ciliates as well as upon the phytoflagellates Isochrysis galbana Parke and Rhodomonas baltica Korsten.Contribution No. 119 from the Institute of Marine and Atmospheric Sciences, University of Miami.     

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.     

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.     

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.     

Factors influencing the gas composition in the vesicles of Sargassum

The composition of gas in the vesicles of Sargassum cf. leptopodum Sonder has been investigated. The oxygen content depends upon the oxygen partial pressure of the surrounding medium. It does not depend upon the photosynthetic activity of the vesicle. Evidence is provided that the lower limit of the vertical distribution zone of Sargassum cf. leptopodum Sonder is not controlled by the vesicles' capability of resisting hydrostatic pressure.     

Distribution of Trypetesa lampas (Cirripedia,Acrothoracica) in various gastropod shells

The distribution of Trypetesa lampas (Hanoock) and its rates of infection of different species of gastropod shells in the waters of Anglesey were studied. T. lampas was found in depths from 3 to at least 25 fathoms (5 to 46 m). It infected dead shells, mainly of Buccinum undatum L., Colus gracilis (da Costa), Neptunea antiqua (L.) and Natica alderi (Forbes); it was absent from shells occupied by hermit crabs in the intertidal zone. Significantly more B. undatum shells were infected than shells of N. antiqua and Natica alderi, and more of both C. gracilis and N. antiqua than of Natica alderi. Larger shells of B. undatum were more likely to be infected than were the smaller ones. The number of females per shell varied with the shell length raised to the power 2.39 instead of as expected with the square of the length.     

Goniadella gracilis,a polychaete new to British seas

Polychaetes of the genus Goniadella Hartman were found in Liverpool Bay, England, in sand and sandy gravel below depths of 15 m. The worms had most of the characteristics of G. gracilis (Verrill), a species previously recorded only from eastern North America and South Africa.     

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.     

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.     

N-acyl homoserine lactone production by bacteria within the sponge Suberites domuncula (Olivi, 1792) (Porifera, Demospongiae)

Many bacteria live in close association with sponges. Within these consortia, molecules of communication such as quorum-sensing and hormone-like molecules may occur in order to regulate the partnership. Of particular interest, bacterial N-acyl-l-homoserine lactones (AHLs) were screened in supernatants from Suberites domuncula-associated bacteria using an E. coli bioluminescent reporter system. These sponge-associated bacteria were beforehand isolated on several media supplemented or not with a sponge extract to attempt to isolate sponge-specific bacteria. Out of 81 AHL-producing bacteria, three strains requiring sponge extract to grow were selected for AHL characterization. The in vitro produced AHLs, that is, in bacterial culture supernatants, were identified as N-(3-butanoyl)-l-homoserine lactone and N-(3-oxododecanoyl)-l-homoserine lactone and quantified using LC–ESI–MS/MS. The in vivo production of AHLs by sponge-associated bacteria has also been demonstrated in a healthy host for the first time: N-(3-oxododecanoyl)-l-homoserine lactone, N-(3-hexanoyl)-l-homoserine lactone, and N-(3-heptanoyl)-l-homoserine lactone. This AHL production in sponges may suggest a potential role of these molecules between sponge-associated bacteria and/or between sponge-associated bacteria and the sponge.     

Bacteriastrum solitarium Mangin,a stage in the life history of the centric diatom Bacteriastrum hyalinum

The initial cell of Bacteriastrum hyalinum Lauder, which is the result of lateral auxospore formation, is identical with the solitary species B. solitarium Mangin. This evidence was obtained in laboratory cultures on B. hyalinum.     

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.     

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.     

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.