Oil/water extraction systems have been devised to study the lipid solubility of metal ions in sea water. Group B metals such as Cu, Zn, Cd, Hg appear to form inorganic complexes in saline solutions that are very lipid soluble. The implications of this are discussed in terms of the penetration of metals across cell membranes.

A frontal region is predicted in Lyme Bay from a numerical model. A crescent-shaped feature is occasionally identified in the coastal-zone colour scanner imagery for this region. Measurements at sea confirm the development of a frontal zone which can show associated increases in levels of chlorophyll a. The surface distributions of inorganic nutrients indicate that nutrients and light levels are factors controlling the observed variations of surface phytoplankton.

A description is given of Squalotrema llewellyni gen.nov., sp.nov., a monocotylid monogenean from the nasal fossae of the spur-dog Squalus acanthias. The parasite differs from representatives of other monocotylid genera in the number and arrangement of loculi on the haptor. In order to accommodate the genus Squalotrema, the diagnosis of the subfamily Merizocotylinae (Yamaguti, 1963) has been amended.

The eggs differ in shape from those of other monogeneans. Each egg appears to be derived from a tetrahedron by flattening of one of the four apices. A long, coiled appendage projects from the flattened apex and the face of the egg from which the appendage projects also bears two spurs. The curved body of the fully developed, ciliated oncomiracidium occupies only two of the three rounded corners of the egg.

A chromatographic/fluorcmetric method was used to measure changes in the proportions of four planktonic dihydroporphyrin pigments during the spring bloom of 1979 in two f jordic sea-lochs, Creran and Etive, on the west coast of Scotland. Very little pheophytin a was detected during the bloom. Chlorophyll a, and to a lesser extent chlorophyllide a, were the two main pigments found during the bloom. During senescence the main pigment breakdown route appeared to be via chlorophyllide a to pheophorbide a. These results suggest that standard methods for measurement of ‘chlorophyll’ which do not distinguish between chlorophyll a and chlorophyllide a might significantly over-estimate the photosynthetic potential of phytoplankton.

The athecate hydroids Coryne pintneri Schneider and Thecocodium brieni Bouillon, previously unreported from British waters, have been found near Oban, western Scot-land. Descriptions and figures are given, with observations on behaviour in culture. It is considered that Coryne pintr.eri is specifically distinct from Coryne filiformis (Rees). The feeding response of Thecocodium brieni is described, and it is concluded that it ismediated chemically by diffusion of exudate from captured prey. Response to mechanical stimulation is also described: it evidently is transmitted through the stolonal network, but it is not known whether this is via nervous or non-nervous tissue. The occurrence in Scotland of thesetwo species, previously known only from north-west France and the Mediterranean, is attributedto their probable introduction on oysters from Brittany, France.

Two new species of hydroid, Sarsia pinforma and Sarsia striata, Family Corynidae, have been found near Oban, west coast of Scotland. Their life-histories have been worked out and their medusae have been reared to maturity in the laboratory. Medusae of striata have also been found in the sea and hydroids have been reared from them. The hydroids and the stages of development of the medusae are fully described and figured, with observations on habits and comparisons with other species of Sarsia. Observations on the development of the gonophores of Sarsia occulta and comments on Sarsia densa are added.

The energetics of leaping (porpoising) in aquatic animals is investigated employing two simple hydromechanical models. The first compares the energy required for swimming at different depths below the surface with that for leaping, the second is employed to calculate maximum cruising speeds in fish and cetaceans for the cases of laminar and turbulent boundary layer flow. Leaping is energetically less efficient than swimming close to the surface up to a certain speed (crossover speed) after which it is more efficient. It is shown that dolphins ought to be capable of reaching the required crossover speeds even if subject to a turbulent boundary layer. This is not so for the larger cetaceans that have been observed to porpoise (e.g. killer whales, Orcinus orca). However, crossover speeds for leaping are well within their scope for the case of a boundary layer that is half laminar and half turbulent. Crossover speeds in pelagic animals that do not undulate a substantial proportion of their body in swimming (e.g. baleen whales and penguins) are relatively high. The crossover speeds of the baleen whales are about four times their observed cruising speeds. It is suggested that these animals swim at speeds at which their filtration apparatus (baleen) operates most efficiently. Pelagic fish do not porpoise and reasons are suggested for this.

Changes in the relative size of the ovary, oviducal glands and eggs are described for Eledone cirrhosa captured from the North Sea off Aberdeen over a 3 year period (N = 488). The analysis is based only on freshly caught animals, excluding those held in aquarium conditions (> 5 days). Ovary enlargement and egg size estimates are used as indices of sexual maturity. Between 0–15% and 18–95% of total body weight is contributed by the ovary. Maximum egg length in the ovary ranges up to 7 mm. On these criteria, sexual maturation typically occurs at body sizes between 400–1000 g although some animals of 1000–1200 g are found showing no evidence of ovary enlargement. The majority of the monthly sample is always immature but maturation can apparently occur at almost any time of the year. Increase in mean ovary index and mean values for egg size are strongly seasonal and indicate a peak incidence of sexual maturity over 2–3 months in the July-September period. Spawning is presumed to follow within 1 month. Estimates of the fecundity of the females, based on the egg sample from the ovary, range from 2·2 × 103 to 55 × 10 3 eggs with a mean of 11 × 10 3 and a mode of 7·5 × 10 3 eggs.

The annual cycle of some physiological conditions in the ormer, Haliotis tuberculata L. was studied by the C:N ratios of foot tissue which were convertible to the glycogen contents, and the coefficients of fatness calculated from two formulae. The former method showed the seasonal change inrelation to the reproductive cycle indicating the foot tissue as a nutritive storage reservoir for spawning, and the latter gave no clear seasonal fluctuation, except a drop of the value shortly afterspawning.

Comparison of ormer populations representing local sites in Guernsey was made by the two methods during the periods of gonad maturation, spawning and pre-spawning (May-October), and the shell forms were analysed by measuring three dimensions of shells, namely, shell length, width and height. The results revealed some changes in physiological conditions between different localities and seasons even within Guernsey. The shell forms also appeared to differ at each site probably as a reflexion of physical and biological conditions surrounding them. The relation of the results obtained by all the methods was discussed to give a more generalized account on physiological conditions of the ormer for its reproduction.

The development of the olfactory system, taste and sensory buds of the Dover sole (Solea soled) during metamorphosis has been studied by light and electron microscopy and preliminary correlations with changes in feeding behaviour have been made.

INTRODUCTION

During metamorphosis, the feeding behaviour of the Dover sole changes considerably. In the early larval phase, the fish swim pelagically, feeding on plankton using their visual sense, while the metamorphosed fish become more active at night, finding food by means of their chemical senses (for a review of the literature, see de Groot, 1971). However, previous observations have shown that sole are capable of feeding in the dark from the very early hatching stage (Blaxter, 1969) and also that at the time of first feeding, the majority of the larvae remain close to the bottom where they appear to ingest particles (Rosenthal, 1966; Fluchter, 1966).

This paper reports a preliminary investigation into physiological and pharmacological aspects of the motor activity of the digestive tract of Octopus vulgaris, with reference tothe relevant anatomy. The results suggest that the octopus gut shows many similarities to somevertebrate guts in terms of functional morphology and motor control. Pharmacological experiments suggest that acetylcholine, noradrenaline and 5HT may act as neurotransmitters and probablyregulate the digestive activity by antagonistic actions, reminiscent of the classical divisions of the vertebrate autonomic nervous system. Histochemical evidence is presented that some ofthese substances are located in the nerves and ganglia of the digestive tract.

The morphology and microanatomy of two different phases in the life history of a single new marine choanoflagellate (Proterospongia choanojuncta sp.nov.) have been documented and described with the aid of light microscopy and from electron microscopy of whole mounts and sections of material in clonal culture. Completion of the life-cycle has been repeatedly achieved in cultures established from single cells, regardless of which phase is used as a starting point. One phase is colonial and motile (the Proterospongia phase) and the other unicellular and sedentary (the Choanoeca phase). Taxonomic, nomenclatural and developmental problems are summarized and discussed.

A new ascothoracid, Isidascus bassindalei gen.nov., sp.nov., has been discovered in the north-east Atlantic Ocean at a depth of over 2000 m. It forms permanent galls on the branches of Acanella arbuscula, a gorgonian of the Family Isidae (Octocorallia, Coelenterata). The new genus is related to Gorgonolaureus, species of which form galls on paramuriceid gorgonians. The gall of the present form unlike that of Gorgonolaureus incorporates a cup of host calcite. Twenty-three adult female specimens and one male were examined in this study. The adult parasite is characterized by elevated humps in a median dorsal position on each of thoracomeres 2,3 and 4. A further feature is a tapering filamentary appendage arising near the base of first thoracopod. The parasite apparently feeds on its host's coenosarc. The likely function of the first and second antennae and each of the three pairs of stylet-form mouth parts is suggested. A case is made for interpretting the species as a protandrous sequential hermaphrodite. Whilst still immature, protanders apparently seek out and settle alongside an adult female. Later, following growth and sexual maturation they again become mobile and after copulation with the nearby female depart to prepare for sex change on a separate branch of the host.

The attachment capabilities of a brown seaweed, Sargassum muticum (Yendo) Fensholt were investigated in the laboratory on both smooth and rough substrata and in surging water motion reaching flow velocities of 57 cm s and 90 cm s.

Newly released zygotes have no means of adhesion until they develop rhizoids, which can adhere on contact with the substratum. Attachment tenacity, as measured by the germling's ability to withstand dislodgement at a given velocity of water flow, is slight at first, but increases with time. This is not simply a function of time spent in residence on the substratum, for germlings cultured suspension stick very quickly and tenaciously when allowed to settle. Tenacity of adhesion seems to be a reflexion of the amount of mucopolysaccharide adhesive present. This increases gradually during the first few days of the germling's life, regardless of whether it is attached or not.

Once secure attachment is achieved it is not weakened even by the death of the germling. A film of bacteria and micro algae on the surface of the substratum is not a requirement for germling adhesion, but its presence enhances the tenacity of adhesion.

Smooth substrata are the least favourable for germling survival in flowing water. On rough substrata the ‘peaks’ of the microtopography and surfaces facing into the current are much less favourable than the troughs between the ‘peaks’, or surfaces in the lee of ‘peaks’. Germling survival increases with increasing substratum roughness up to an optimum rugosity at which the mean depth of the depressions on the surface is 420 μm, and the vast majority are deeper than the height of the germlings.

Serial-section electron micrographs have been obtained of the phagocytosis of Prochloron cells by amoebocytes of the ascidian Lissoclinum voeltzkowi (Michaelsen). This may answer the hitherto puzzling question of how the host tunicate benefits from photosynthetic symbionts situated in an excurrent water flow.

Based on the morphology of the mandible, female maxilliped, and male first endopod, Lichomolgus longicauda (Claus) is transferred to Metaxymolgus Humes & Stock, 1972. M. longicauda is recorded for the first time from Sepia officinalis L. taken in British waters.

The behaviour and physiological responses of Mytilus edulis L. to increased concentrations of copperare dependent on the absolute copper concentration present and not the rate of increase of concentration. The sequence of behavioural responses isolating the animal from heightened sea-water copper concentration is similar to that observed in response to lowered salinities. The effects of copper onthe oxygen consumption of intact and ‘propped open’ and animals whose posterior adductor muscles havebeen severed suggest that only measurements of animals in the latter state give a true reflexion of the effects of copper on the oxygen consumption of the tissues of Mytilus. The effects of increased sea-water copper concentrations on the filtration and ventilation activity of mussels are assessed, but consideration of the data in terms of Dejour's equation of gaseous exchangesuggest that indirect measurement of ventilation activity gives rise to differing results. The adaptive advantage of theresponse of Mytilus to heightened sea-water copper concentrations is considered.

Observations in the field, and in the laboratory, of littoral fishes of south-west England during the period 1978–80 have shown that the three blenniid species found with any frequency on the shore constitute an important link in food chains. The occurrence, age, habitat and diet of Blennius (Lipophrys) pholis L., Coryphoblennius galerita L., and Parablennius gattorugine Brunnich have been considered; B. pholis was by far the most common of the three, with very few P. gattorugine being found intertidally. Of the latter, only age groups 0, 1 and 2 were represented in the littoral populations, whereas in the truly littoral species age groups 0–10 were found for B. pholis and 0–6 for C. galerita. Measurements of growth rates for the three species have been compared with growth rates of B. pholis and C. galerita at other sites, and a similar treatment has been afforded to dietary constituents. A discussion of the possible competition for food and refuge between the three species, and with other littoral teleosts, concludes that highly efficient partitioning of resources reduces competition to a minimum, with the exception of abundant food items which are (in any case) probably underexploited.

The red muscle of the thresher-shark myotome is internalized and supplied by a simple rete in connexion with lateral vessels. It is probable that the system enables the fish to be warm-bodied.

INTRODUCTION

Warm-bodied sharks were first described by Carey & Teal (1969); subsequent observations by Carey and his colleagues (Carey et al. 1971) and by Carey (1982) showed that five lamnid species were able to maintain body temperatures 5–10 °C above the ambient water. All of these possess more or less elaborate retia linking a red muscle mass lying internally in the myotomes with the systemic circulation. In cold-bodied sharks, the red muscle lies superficially, just under the skin, and retia are absent. A sixth lamnid species, the big-eye thresher shark (Alopias superciliosus) may be warm-bodied; it has a simple muscle retial system (Carey et al. 1971) which has not been described in detail. The chance capture of a common thresher shark (A. vulpinus) enabled this short description of the retial system in this species.

The salmon shark, Lamna ditropis Hubbs and Follett, is a streamlined, pelagic predator capable of rapid swimming locomotion, very similar to its close relative, the Atlantic porbeagle, Lamna nasus (Bonnaterre). The porbeagle is warm-bodied, maintaining deep body temperatures 7–11 °C above those of the surface water from which they are captured (Carey & Teal, 1969a). Presumably, Lamna ditropis is also warm-bodied. Opportunities to measure temperatures of salmon sharks occurred on 2, 4 and 5 September 1979, when one of us (D.R.) hooked and landed three salmon sharks while hand-trolling for salmon. The sharks were all caught near Cape Edgecumbe, about 60 km from Sitka, Alaska (57° 6´N, 135° 55´ W) at a depth of 12–40 m.