Distinctive flask-shaped cysts have been observed within the loricae of the tintinnids Favella serrata (Mobius),Helicostomella subulata (Ehrenberg), Parundella caudata (Ostenfeld) and Leprotintinnus pellucidus (Cleve) from samples taken by the Continuous Plankton Recorder. Similar cysts occur as a common element in palynological preparations of intertidal sediments from the British Isles. Encystment in tintinnids is now known for over 20 species and appears to be a more important process in the tintinnid life-cycle than previously believed. A possible relationship between tintinnid cysts and the extinct microfossil order Chitinozoa is proposed.

Observations during four dives in the submersible ‘Alvin’ in June 1976 revealed that ctenophores were the most abundant large plankters between 400–700 m. From specimens collected with a slurp-gun device, Bathocyroe fosteri gen.nov., sp.nov., a species characterized by strong lobes, large auricles and red pigmentation of the gut, is described. Few ctenophores have been collected previously from deep water, but observations from submersibles indicate that several species occur throughout the mesopelagic zone.

The arrangement of the ciliary sensory organs regularly arrayed on the body is re-described, and it is concluded that these are what are visible as bristles in life. On the head and tail region there are, in addition, stout single cilia, which contain multiple internal tubules, and on the head alone, there are presumed sensory cells which contain cilia within invaginations of the cell surface. Small bunches of pointed bristles occur scattered over the body surface; these are entirely distinct from the sensory cilia.

The second maxilla is innervated typically by 35 motor neurones in Nectocarcinus antarcticus and about 39 in Cancer novaezelandiae. Muscles are multiply innervated. Within one species variations in the number of motor neurones innervating any muscle do occur but are not common.

The distributions of Corophium insidiosum and C. bonnellii on the shores of Northumberland and Tyne and Wear suggest the former species to be common in areas of high turbidity, and the latter species in relatively clean conditions. In C. insidiosum breeding takes place throughout the year except during the months of November and December when mature females enter a ‘resting’ stage and immature females delay the onset of maturity. There are two main generations per year. Egg production is linked to a semi-lunar rhythm with peaks around the times of spring tides. Fecundity, brood mortality and feeding activity each vary seasonally.

A steroid that binds with mammalian oestradiol-17β antibody has been detected in Calanus helgolandicus Claus, collected from Plymouth Sound, and in Calanus finmarchicus Gunnerus captured off the coast of Norway. The specificity of the antibody, together with the chromatographic behaviour of the steroid on Sephadex LH-20, supports the view that the compound is the sex hormone oestradiol-17β (E2). The antibody has been used in measuring the amounts of E2 in the animals by radioimmunoassay, a technique not previously employed in studies with zooplankton and therefore described in detail.

In spite of a specialized shell structure and an obligate coral-inhabiting mode of life, B. anglicum retains a generalized balanoid operculum, cirri and mouthparts. These are used to capture and ingest live planktonic prey such as nauplii. Prolonged cirral extension is a preliminary to prey capture but the capture process itself involves the beating down of the prey by a series of up to six contractions and extensions of the cirri in 7–10 s. The prey is then grasped by the extended third maxillipeds (cirrus III) and drawn into the mantle cavity. An antenniform exopod of cirrus I is extended and detects the prey at the beginning of the capture sequence. The exopods of cirrus I are also used in the rejection of any unwanted particles grasped and taken in by the third maxillipeds.

During surveys of rocky shores in Shetland, the Australasian barnacle Elminius modestus was found at 3 out of 42 transect sites and at 6 out of 11 shores searched for its presence. Large populations were present only in Vidlin Voe with a few individuals present at other sites including Lerwick Harbour. These observations extend the northern recorded limit of distribution of E. modestus by approximately 450 km.

The spread of the Australasian barnacle Elminius modestus Darwin along the coasts of the British Isles has been followed with interest by marine biologists since the animal was first found in the region of Portsmouth in 1946. Crisp (1958) describes the spread of Elminius up to 1957 and reviews the factors which are important in encouraging or restricting the spread of the species. On the west coast of Scotland, Elminius is common in the Clyde and a few individuals have been recorded on settling panels in Dunstaffnage Bay near Oban (Barnes & Stone, 1972). On the east coast of Scotland, Elminius is known to be common in the Firth of Forth and a few individuals have been recorded from the Tay Estuary (Jones, 1961). Thus, the previous recorded northern limit of distribution of Elminius modestus lies at about 56° 30′ N. Our brief report describes how Elminius has now been found in the northernmost part of the British Isles.

As a part of the programme designed to monitor the effects of the oil terminal now being built at Sullom Voe on the north-east coast of the Shetland mainland, we have been concerned with the survey of plant and animal populations on rocky shores.

The structure of the fifth pair of pleopods, modified as secondary sexual characters, in male Euchaeta norvegica is described in detail. The pleopods are biramous. The right pleopod, of relatively simple structure, is used solely to grasp the urosome of the female during transfer and placement of the spermatophore. The left pleopod is complex in form and is used to grasp the spermatophore as it is extruded from the ductus ejaculatorius. The method of grasping the spermatophore is described. The optimal mating position is deduced from the structure and functioning of the pleopods.

The release of larvae by female lobsters is confined to a few minutes at night, and is repeated at a similar time on each night over several weeks. The rhythm is shown to be partly controlled by an endogenous component in the female. Eggs in vitro have an exogenous, light-stimulated hatching rhythm, but are arhythmic in continuous light or darkness. In light/darkregimes the time of hatching is not influenced by daylength, but occurs sooner after sunset astemperature increases.

The shell closure mechanism of Mytilus edulis protects the frontal ciliary mechanism against irreversible damage by low environmental salinity levels. Previous experiments had shown that the mantle fluid of mussels exposed to fluctuating salinity regimes was held at a concentration corresponding to about 60% s.w. (20·1‰S) during the period of shell valve closure (Shumway, 1977), while the oxygen tension of the mantle cavity fell rapidly after shell valve closure to 15 mmHg and thereafter remained relatively constant until the valves reopened (Bettison & Davenport, in preparation). These conditions of salinity and oxygen tension were applied to experimental preparations and their ciliary activity assessed. The salinity conditions alone depressed activity by 39·5%. The conditions of oxygen tension alone also produced a depression of 39·5% but there were signs of recovery during the period of simulated shell valve closure. When both salinity and oxygen tension conditions were applied simultaneously a more profound depression of 64·4% was produced by the interacting factors. Exposure of preparations to salinity levels corresponding to the external environment (‘no closure’ simulation) irretrievably damaged the frontal ciliary mechanism on the first exposure to low salinity.

The sipunculanPhascolion strombi (Montagu) is well known for its habit of sheltering in empty mollusc shells. In European waters, a variety of animals are to be found associated with this sipunculan in its shelter (see Kristensen, 1970), including the pyramidellid gastropodMenestho diaphana (Jeffreys) and the erycinacean bivalveMontacuta {Tellimya) phascolionis Dautzenberg & Fischer. Neither of these two species has been recorded as living in association withP. strombi in British waters but a recent examination ofP. strombi-inhabited shells in the vicinity of Plymouth has shown both to be present in the area.

Like all pyramidellids, M. diaphana is an ectoparasite although for many years after its description by Jeffreys (1848, as Odostomia) from Exmouth, Devon, its host animal(s) remained unknown. It was first discovered associated with P. strombi by Perez (1924, 1925) at Roscoff, Brittany, and subsequently described by Dautzenberg & Fischer (1925) under the name Odontostomia (Auristomia) perezi. The possibility ofO. perezi being synonymous with the speciesdiaphana, placed in the genus Menestho by Fretter & Graham (1962), was first suggested by Thorson (Thorson, in Robertson & Orr, 1961), a view supported by Ockelmann (Ockelmann, in Ankel & Christensen, 1963) and Kristensen (1970). Recently, Rodriguez-Babio & Thiriot-Quievreux (1974) demonstrated that the protoconchs of the' free-living' individuals (M.diaphana-type) are similar to those of individuals living withP. strombi (O.perezi-xype). In shell shape, specimens associated withP. strombi at Plymouth closely resemble the holotype ofO. diaphana, now in the collections of the Smithsonian Institution (V. Fretter, personal communication). Thus & Fischer named O. perezi without reference to it would appear that Dautzenberg O. diaphana material, or perhaps were impressed sufficiently by its regular association strombi as to regard it as a distinct species. In either case, it seems to have been now established that perezi is a synonym of diophana.

The growth of Chlamys opercularis from three sites in the Firth of Clyde has been studied. A relationship exists between the different dimensions of the shell, but, because growth is allometric, these relationships do not remain constant throughout the life of the animal. In contrast to the rectilinear relationship between the shell dimensions, the cavity volume and the weight of the shell and the weight of the soft tissues increases exponentially with increasing shell height. The growth rings on the shell of Chlamys were shown to be truly annual and are deposited primarily during the period from April to June, providing a convenient and reasonably accurate technique for assessing the age of individual animals. The size range of the height of the first ring was quite large, with a bimodal frequency distribution. The bimodality is lost in the second and subsequent years due to differential rates of growth between large and small first-year animals. The rate of growth of Chlamys from the Clyde Sea area was determined from values for the mean height of each annual ring, and has been compared to the rates shown by Chlamys from other sites around the British Isles.

Terms, dimensions and ratios for statolith description are defined. The form of the calcareousstatoliths in the Teuthoidea, Sepiodea and Octopoda is described by reference to Loligo forbesi, Sepia officinalis and Eledone cirrosa. While statoliths change in form and size during the growth of a cephalopod, the adult form is often characteristic for a species, despite some variation. Description of statoliths is important in studies of the fossil remains of cephalopods lacking calcareous shells, and will probably become important in the taxonomy of living species, in food analysis of cephalopod predators and in the study of deep sea deposits.

The first species ofLamellisabella to be described from the Atlantic Ocean has rows of small teeth on the tentacles. It occurs at about 4000 m depth in the Bay of Biscay, and its range probably extends along the continental rise at least as far south as the Gulf of Guinea.

Plasma vitellogenin synthesis in adult female Scyliorhinus canicula L. continued throughout the year but the rate of synthesis was significantly lower between March and August than during the rest of the year. The hepatosomatic index (liver weight as percentage of body weight) underwent annual variation in both sexes but this variation was considerably more pronounced in the female. Increase in hepatosomatic index in the female was accompanied by increase in the percentage of lipid in the liver and was largely caused by increase in the total lipid content of the liver. Comparison of livers of males and females showed that the percentage of lipid was not significantly different while the percentage of solids insoluble in water and organic solvents was greater in the female. Oviposition, as indicated by the percentage of females with eggs in the oviducts, continued throughout the year, reaching a minimum in September-October. Between July and October, parameters associated with vitellogenesis began recovery from their respective annual minima in the following order: plasma oestradiol level, hepatosomatic index, rate of synthesis of plasma vitellogenin, gonosomatic index, plasma vitellogenin level, rate of oviposition.

Activities of phosphomonoesterases were measured at acid and at alkaline reaction (pH 4–5 or 9–65) in homogenates of elasmobranch tissues especially lymphomyeloid structures. The animals were dogfish (Scyliorhinus caniculd) and two species of ray (Raja brachyura, R. naevus). Acid phosphatase activity was high in the epigonal tissue, Leydig's organ, the spleen and the thymus. High activity was also found in the pancreas and the kidney, whereas skeletal and cardiac muscle showed low values. The activity of alkaline phosphatase was very high in the kidney and relatively low in other tissues. Ultrasonification of homogenates from the dogfish resulted in increase of acid phosphatase activity but had little effect on alkaline phosphatase activity. The high activity of acid phosphatase in lymphomyeloid tissue may be due to the presence of large numbers of various types of leucocytes.

Citadel Hill, Plymouth (Plates I–II) The sexual display and mating of the dragonet (Callionymus lyra L.) were well described by Holt in 1898 from observations of the behaviour in a relatively small tank in the Plymouth aquarium. When in 1959 numerous dragonets werekept in a much larger tank mature males established territories within which they displayed tofemales. The more pugnacious males maintained larger territories than less pugnacious males. Maintenance was mainly by display against rivals without physical contact, but occasionally there were direct attacks in which minor damage was inflicted.

In his long and detailed account of the sexual display and mating of the dragonet (Callionymus lyra L.), based on observations in the Association's aquarium at Plymouth, Holt (1898) makes no mention of males defending specific areas and states that there was 'no evidence of serious combat among mature males' (p. 312). 'Occasionally the two males meet in full splendour. Then one lowers his colours and flies ingloriously; but I have never seen anything in the shape of a fight, and have never found wounds that might have been inflicted when I was not watching' (p. 288). Holt records (p. 286) that his dragonets inhabited a tank on the south side of the aquarium and it was in that tank that breeding displays took place. He also put large males into a very much larger tank, though only to watch their reactions in the presence of large turbot (p. 295): one was eaten, others disappeared not to be seen again.