The cyphonautes larva found in certain ectoproct Polyzoa is considered to be most probably a primitive larval form, which has been lost in viviparous species, the larvae of which are degenerate in varying degree and settle within a short time. The cyphonautes is truly planktonic and has a free swimming Life of some length—of 2 months according to Marcus (1940, p. 334)—and unlike the other known larvae of the group, has a functional alimentary canal. It obtains its food by maintaining a continuous current of water through the mantle cavity or vestibule, its ciliary mechanism being organized on a plan somewhat resembling that of bivalve molluscs, with an inhalant and an exhalant chamber with interposed ciliary ridges bearing current-producing and food-conveying cilia. As in lamellibranchs the organ creating the water and food currents is separated by a considerable interval from the mouth. In lamellibranchs this interval is bridged by the palps and the oral grooves; in the cyphonautes by the ciliated tract of the funnel. The cyphonautes being a larval form of probably archaic character its method of feeding is of particular interest.

We describe the phytoplankton community and biomass during a summer coccolithophorid bloom sampled over the Patagonian shelf (48.5°S–50.5°S). Those phytoplankton species can contribute to the flux of calcium carbonate out of surface waters. Results from both microscope and high-performance liquid chromatography (HPLC) analysis are shown to complement information on the phytoplankton community. From CHEMTAX analysis of HPLC data, the most important organisms and groups identified were the coccolithophorid Emiliania huxleyi, the haptophyte Phaeocystis antarctica, dinoflagellates, diatoms, cryptophytes, prasinophytes and cyanobacteria. Phytoplankton microscope counts were converted into phytoplankton group-specific biovolume estimates. Although some microscope-identified taxa could not be determined by CHEMTAX, e.g. the autotrophic ciliate Myrionecta rubra, cluster analyses from both techniques showed similar results for the main groups. Both Emiliania huxleyi cell concentration and biomass, and the pigment 19′-hexanoyloxyfucoxanthin were the most important biological features during the sampling period. At surface, nitrate was moderately high (0.2–4.2 µM) in coccolithophorid-dominated samples, whereas phosphate (<0.33 µM) and silicate (<1.35 µM) concentrations were low. Among the environmental factors low Si:N ratios were mainly associated with the dominance of E. huxleyi. Competition and probably differential grazing could also promote a coccolithophorid outgrowth over other photoautotrophs during the summer season in the Patagonian shelf.

Generation of ion electrochemical potential differences by primary active transport can involve energy inputs from light, from exergonic redox reactions and from exergonic ATP hydrolysis. These electrochemical potential differences are important for homoeostasis, for signalling, and for energizing nutrient influx. The three main ions involved are H+, Na+ (efflux) and Cl− (influx). In prokaryotes, fluxes of all three of these ions are energized by ion-pumping rhodopsins, with one archaeal rhodopsin pumping H+into the cells; among eukaryotes there is also an H+ influx rhodopsin in Acetabularia and (probably) H+ efflux in diatoms. Bacteriochlorophyll-based photoreactions export H+ from the cytosol in some anoxygenic photosynthetic bacteria, but chlorophyll-based photoreactions in marine cyanobacteria do not lead to export of H+. Exergonic redox reactions export H+ and Na+ in photosynthetic bacteria, and possibly H+ in eukaryotic algae. P-type H+- and/or Na+-ATPases occur in almost all of the photosynthetic marine organisms examined. P-type H+-efflux ATPases occur in charophycean marine algae and flowering plants whereas P-type Na+-ATPases predominate in other marine green algae and non-green algae, possibly with H+-ATPases in some cases. An F-type Cl−-ATPase is known to occur in Acetabularia. Some assignments, on the basis of genomic evidence, of P-type ATPases to H+ or Na+ as the pumped ion are inconclusive.

Habitat preference and spatial distribution of Guiana dolphins (Sotalia guianensis) in Norte Bay, southern Brazil, was studied from 2001 to 2005. Boat surveys (N = 91) were made to evaluate the spatial distribution of the dolphins. Seven habitat variables were integrated into a geographical information system, and habitat preference was tested using the ‘Neu method’ and a habitat index. The Guiana dolphins did not use all habitat types in the same proportion as were available. Areas used more intensively included, in order of importance: (1) areas with a steep sloping sea-floor; (2) areas further from urban areas; (3) areas further from mangroves; (4) areas near the mouth of the bay; (5) shallow water areas; (6) areas of clayey-silt sediments; and (7) areas close to shore. From 2001 to 2005 there was a shift in spatial distribution and habitat use by the dolphins. The low frequency of use of areas close to urban encroachment and its related impacts to the marine environment raises concern about the coastal habitat destruction. The Guiana dolphin may be considered a habitat specialist, despite its wide latitudinal distribution in the western Atlantic Ocean. The ecological niche of the species may be defined by a narrow strip of shallow coastal waters (mostly < 30 m) bordering the coastline. The shift in the spatial use was probably linked with changes in the abundance of important prey of the species and possibly was caused by the collapse of a fish stock in the study area region. Different habitats may favour different assemblages of prey and consequently different foraging strategies by the dolphins. Human-related habitat alterations throughout the range of this species are likely to affect dolphins' ecology in many ways and, thus, must be evaluated and mitigated to conserve their critical habitats.

This study reports the morphometric relationships and relative growth of 20 uncommon bivalve species collected along the Algarve coast (southern Portugal). Morphometric relationships were established between three linear variables (shell length, height and width) and one ponderal variable (total weight) and the relative growth between variables (isometry vs allometry) was analysed in order to assess their variation throughout ontogeny. In addition, morphometric indices (elongation, compactness, convexity and density) based on ratios of those linear and ponderal variables were calculated in order to further characterize morphologically the bivalve species. A total of 2512 individuals belonging to nine bivalve families were analysed, comprising specimens with broad ranges in both shell length (11.8–109.0 mm SL) and total weight (0.2–354.6 g TW). All morphometric relationships were highly significant (P < 0.001) and displayed invariably high correlation coefficients (r = 0.727–0.998). Among a total of 60 morphometric relationships, 27 isometries, 25 positive allometries and 8 negative allometries were registered. The morphometric indices displayed a remarkable variation among taxa, reflecting the high morphological diversity of these miscellaneous bivalve species. Discriminant analysis provided a spatial visualization of the species morphometric variables that further evidenced their main shape features, the distinctness between some species and families (e.g. Pharidae and Cardiidae) and the morphological resemblance among some species belonging to other families (e.g. Veneridae and Tellinidae). Overall, this information is useful and has practical application in diverse research fields, including studies on systematics and taxonomy, physiology, biology, ecology, fisheries assessment and management.

In the present study a comparison of the otolith morphology of two species of parrotfish, family Scaridae, collected from the Red Sea coast of Egypt, is conducted to identify the most appropriate taxonomic characters that separate these species. Ontogenetic changes in the otoliths of the two scarid fishes become evident. In the otoliths of Chlorurus sordidus, the following characters are comparable in small-sized adult fishes: otolith width, otolith depth, mesial surface shape, lateral surface shape, shape of sulcus acusticus, column, rostrum and size of rostrum. The otoliths of young adults (GI) C. sordidus differ from the adult ones in 14 out of the 22 characteristics studied. In the otoliths of Hipposcarus harid, the following characters are comparable in small and large fish: otolith width, otolith depth, mesial and lateral surface shapes, shape of sulcus acusticus, rostrum and size of rostrum.

Jørgensen (1944) showed that young specimens of the siliceous freshwater sponge Spongilla lacustris L. obtained their skeletal silica from the water and demonstrated that, under experimental conditions, a relationship existed between the size of the microscleric spicules produced and the concentration of dissolved silicate in the culture medium. The thickness of the microscleres increased with increasing concentration of dissolved silicate in the medium but no changes were detected in the lengths of the microscleres or in the size of the megascleres. Prior to this report Jewell (1935) showed that specimens of 5. lacustris with normal spiculation were rarely found in natural waters with a silicate content below 0.005 to 0.01 mm Si02. Hartman (1958) suggested that the greater thickness of siliceous spicules found in specimens of Haliclona caniculata Hartman collected in winter from New England shores, compared with spicules from summer-collected specimens, might reflect the increased concentration of dissolved silicate in the sea water during the winter months. Similar effects have been demonstrated experimentally in calcareous sponges: Maas (1906) showed that calcareous sponge larvae reared in calcium-free water produced no mineral spicules but organic ‘spiculoids’ of similar form. A relationship between spicule size and environmental silicate has not, in the past, been conclusively demonstrated for any siliceous sponge in field conditions.

Carlisle (1954) described Styela mammiculata, a new species of stalked ascidian from the Plymouth area, and suggested that it had been brought into British waters, probably with oysters. Its recent discovery on other parts of the south coast of England (Houghton & Millar, 1960) supports the idea that it is an introduced species which is now spreading through a favourable environment. It is well, therefore, to consider whether this may not be a species known from another part of the world. Tokioka (1955) examined one of Carlisle's specimens and suggested that it fell within the range of variation of S. clava Herdman. As many specimens of S.mammiculata are now available, a more extensive comparison has been made and is reported in this paper.

Growth of shells of larvae of Nassarius reticulatus (L.) and Crepidula fornicata (L.) reared in the laboratory under constant temperature (14 °C) and illumination (155 lx) occurs by the addition of successive strips secreted at the mantle edge. Growth lines on the embryonic teloconch also indicate intermittent growth; the protoconch secreted by the shell gland has no such lines. There is evidence that growth periods are short and pauses separating them prolonged. The diameter of the older whorls of the shells of these and six other species examined increase with the volume of the viscera. This change in diameter is made possible by the flexibility of the organic matrix, the funda-mental constituent of the shell. The matrix, secreted as fibres at the mantle edge, forms sheets, and provides sites for the deposition of calcareous concretions; at metamorphosis the concretions apparently initiate the formation of crystals. The concretions also sculpture the surface of the shell producing a pattern sufficiently conspicuous to allow identification of some species with the aid of only the stereomicroscope. For example, large concretions form longitudinal rows over the protoconch and teloconch of Littorina neritoides (L.) and smaller ones combine to form a more decorative pattern in Rissoa sarsi Loven. In other species details of the surface design require a scanning electron micro-scope. Interspecific differences in the arrangement of concretions may be traceable to differences in the pallial glands which secrete the matrix.

The reproductive biology of two epizoic deep-sea anemones reveals contrasting reproductive strategies. Amphianthus inornata (Cnidaria: Anthozoa) lives attached to the bathyal gorgonian Acanella arbuscula (Cnidaria: Anthozoa). Females of A. inornata increase in wet body weight as a result of increased oocyte production until 40% of the body weight is reproductive tissue. The anemone reproduces on a seasonal basis, releasing eggs in the early spring of each year. By contrast, Kadosactis commensalis (Cnidaria: Anthozoa) lives attached to the body wall of the abyssal holothurian Paroriza prouhoi (Echinodermata: Holothurioidea). This anemone is a protandric hermaphrodite, females being found only at the anterior end of the holothurian, whilst males are found at any point on the host. Females have a significantly higher wet weight than males and neither sex shows any reproductive seasonality.

The stomach is the principal region of extracellular digestion in the alimentary tract of Ciona intestinalis (L.) (Yonge, 1925; Morton, 1960). The region is oval and has a lining epithelium thrown into 30 or 40 longitudinal ridges. Previous authors have described the following cell types in this gastric epithelium: a mucous cell (Roule, 1884; van Weel, 1940); an un-differentiated cell (Yonge, 1925; Millar, 1953; Fouque, 1954); an absorptive cell (Yonge, 1925; Berrill, 1929; van Weel, 1940; Morton, 1960); a storage cell (Yonge, 1925; van Weel, 1940) and several different secretory cells (Roule, 1884; Yonge, 1925; Berrill, 1929; van Weel, 1940; Millar, 1953; Fouque, 1954; Morton, 1960). The present paper reports a re-investigation of the gastric epithelium by histochemical methods and by electron microscopy, and a comparison of the observations with those of previous authors. The fine structure of the gastric cells is compared with that of cell types in the ‘liver’ of Pyuridae (Degail & Lévi, 1964) and in the alimentary tract of other animals.

A new species of Hirondellea was trapped in large numbers (N=441) in the Atacama Trench (Pacific Ocean) at 7800 m depth. The species accounted for 47% of the total number of amphipods collected and was the second most abundant amphipod after Eurythenes gryllus. Adult males and females reached maximum lengths of 13·5 and 14·1 mm. Length–frequency histograms showed no clear evidence of growth classes, but instars could be determined by using a combination of morphological criteria and size–frequency data. Growth factors based on mean lengths of successive instars ranged from 1·09 to 1·24 except at moults immediately prior to maturity when factors were in the range 1·02–1·04. Females moult from the pre-adult to the adult instar, without body growth. Moulting modalities of immature males are unclear. Equations obtained from regression analysis between wet weight and total body length indicate an allometric growth. Females grow at a rate of 10% higher than males, and both females and males display growth rates lower than those observed for juveniles, but growth increments at each instar of females are not significantly higher than those of males. The relationship between total body length (L) and wet weight (W) of all instars of Hirondellea sp. nov. is expressed by the power curve W=0·012 L3·279 (W in mg and L in mm).

Characterization of suitable habitat for settlement of juvenile flatfish is important for the management of nursery areas. Food availability is one important determinant of habitat quality that can affect the condition and growth, and thus survival, of flatfish. Spatial and temporal variation in diet has been widely studied for several species of flatfish. However, levels of intraspecific variation in diet at small spatial scales are relatively unknown, with most studies focusing only on large scale variability. This study investigates how diet, growth and condition of juvenile plaice, Pleuronectes platessa, varies over two spatial scales (10s of kilometres and 100s of metres). Juvenile plaice were collected from three beaches and from three replicate hauls on each beach using a beach seine in September 2007 and 2008. Gut content analyses of 108 juvenile plaice within the size-range of 70–90 mm were carried out. Diet composition in plaice guts differed among beaches and hauls suggesting that food abundance and availability differed at both spatial scales. A significant positive correlation was observed between a morphological condition index and the prey diversity in the gut. This suggests that fish which specialize on a limited number of prey items (perhaps due to a greater abundance of certain prey) may do better than fish which feed on a wide range of prey types. Significant differences in condition were observed between hauls and between beaches, while recent and total otolith growth varied between beaches but not between hauls. The results highlight the importance of considering small scale variation when attempting to link habitat quality to feeding, growth and condition of juvenile flatfish.

This is the second of three papers describing the structure, properties and buoyancy function of the spermaceti organ of the sperm whale (Physeter macrocephalus Linnaeus 1758). The first paper (Clarke, 1978a) described the detailed structure and proportions of the spermaceti organ and related structures and considered relevant details of the blubber, skin and lungs. Here, three thermal properties of the spermaceti oil are described which are relevant to a study of the function of the oil. Finally, in a third paper (Clarke, 1978b) it will be shown that, over its great geographical and depth ranges, the whale varies considerably in buoyancy due to variations in water density and the volume of air in its lungs and it is suggested that, during dives, the whale can control its own density by changing the temperature of the spermaceti oil of the head and may attain neutral buoyancy in dives deeper than 200 m.

The relationships between the standing stocks of deposit-feeding benthic invertebrates and benthic chlorophyll-a, phaeopigment and total combustible organic matter were investigated at a series of coastal lagoons and in the type of intertidal soft-sediment sites from which the lagoons originated. Across all the sites, in Norfolk, UK, an inverse relationship occurred between (a) the amounts of chlorophyll-a and of other potential food materials and (b) the degree of coverage by water. The biomass of consumers also decreased with increased water coverage, so that the lagoons supported less biomass than the adjacent high-level intertidal sites. Further, the deposit-feeder biomass supported by unit food decreased with extent of water coverage.

There was no evidence of any relationship between deposit-feeder and food biomass within any single site, in spite of the study period being selected to be that in which there was maximum likelihood of competition for microphytobenthic food. Whilst chlorophyll concentrations may set the maximum achievable level of consumer biomass at these sites, including in the deeper lagoons setting very low potential maximum population densities, the seasonal abundance patterns of the deposit feeders appear to be determined by other factor(s).

Paraphysomonas cribosa n.sp. possesses two unequal flagella, one short and smooth, the other long, bearing numerous fine hairs. The cell surface is covered with scales which are resolvable using the electron microscope. These are polymorphic, built of rods and generally having an oval periphery. Struts from this support an inner oval ring, and further struts support a central perforated area.

Expected lifetime investment in eggs and related parameters are described for a lagoonal population of Hydrobia ventrosa (Mollusca: Gastropoda) in East Anglia, UK, and these are compared with those of East Anglian lagoonal populations of H. neglecta and both lagoonal and intertidal-marine populations of H. ulvae. In contrast to an earlier study on Danish populations, which suggested that H. neglecta and H. ventrosa are at opposite ends of the hydrobiid spectrum of investment in reproduction, the order of increasing relative allocation of resources to egg production runs H. neglecta = H. ventrosa → lagoonal H. ulvae → intertidal-marine H. ulvae. That is, from the two small, short-lived, specialist lagoonal species producing few, large, directly-developing eggs, to the larger, potentially longer-lived H. ulvae that produces many small eggs which develop into veliger larvae. The lagoonal populations of all three Hydrobia species, however, are very similar to each other in terms of reproductive investment. When like cohorts are compared, in each, the annual egg weight is equal to the annual adult growth increment, and the weight of eggs produced per expected lifetime is half the adult growth increment at the time of death. These lagoonal populations are markedly dissimilar to intertidal-marine populations of H. ulvae, which produce an annual weight of eggs some 15 times the annual adult growth increment, and an expected lifetime egg weight some two-and-a-half times the adult growth increment at the time of death.

A 6·1-m long female basking shark (Cetorhinus maximus) was tagged 73 km east of Nantucket Island, Massachusetts on 27 September 2001 with a pop-up archival transmitting tag. The tag detached prematurely on 6 December 2001 in an area approximately 800 km south-west of the tag site off the coast of North Carolina. The basking shark was vertically active for the 71-d tracking period, moving through depths and temperatures ranging from the surface to 320 m and 5·8 to 21·0°C, respectively. The shark displayed temporal variation in its residence depth and exhibited a marked temperature preference, with 72% of the temperature observations between 15·0 and 17·5°C. This track provides evidence that the basking shark associates with the continental shelf and shelf edge off the south-eastern United States during autumn. Moreover, it corroborates previous studies indicating that the basking shark remains active and does not hibernate during autumn.

The distribution and ecology of subspp. anceps and edentatus of F. distichus L. emend. Powell (1957) in Britain and Ireland is described in detail, based on recent ecological surveys and critical examination of all past records.

F. distichus anceps is a small form confined to certain very exposed coasts in the north and west of Scotland and Ireland, where it reaches the southern limit of its geographical range. This plant may be a relict form in Britain, existing now only under an extraordinarily narrow range of rigorous habitat conditions; it is not thought to be actively extending its range southwards at the present time. The ecology of subsp. anceps is considered principally in relation to that of other reduced fucoids found on exposed British shores, viz. F. spiralis f. nana and F. vesiculosus f. linearis; all three forms are illustrated by photographs and means of distinguishing them are described. The lifespan of subsp. ancepsis thought to be 2 to 3 years at some Irish sites, but may be longer at some of the Scottish sites.

Tube-dwelling diatoms are found in a variety of habitats, from marine to fresh water on different types of substrata; rock, wood, plant and animal. I have described species as tube-dwelling (Cox, 1975 b) if they produce mucilage which is consolidated into a tubular structure around the cells, yet within the mucilage tube individual cells move and divide. The tube is usually attached to the substratum at its base and is extended apically by the secretion of more mucilage by the enclosed diatoms. Tube volume thus increases to accommodate the increased endotubular diatom population. The presence of tube-dwelling diatoms on rocky shores has been recorded by some workers (Aleem, 1949, 1950; Castenholz, 1963, 1967; Hopkins, 1964), while Castenholz (1963, 1967) correlated seasonal and distribution patterns of some littoral species with their response to light intensity and day-length. Carter (1932,1933) described the algal flora, including several tube-dwelling species, of two salt marshes but little work has been done on tube-dwelling diatoms occurring in estuaries. During the course of a study on the biology of these diatoms (Cox, 1975 ft) variation in their distribution at two Severn Estuary sites prompted an investigation into their distribution in the estuary as a whole. Diatom distribution was recorded with reference to the geographical location in the estuary and to the position on the shore at two sites lower down the estuary (Clevedon and Weston-Super-Mare).