The phenomenon of epitoky in polychaetes, in which maturing individuals of benthic species undergo metamorphosis and then swim to the surface of the sea for spawning, has been extensively documented (see Fage & Legendre, 1927; Clark, 1961 for references). The death of individuals after spawning has been widely recorded and has been assumed to apply to all swarming species of polychaetes. However, Herpin (1925) recorded the survival of Pionosyllis lamelligera and Eusyllis blomstrandi after they had swarmed and spawned. He noted the loss of the swimming chaetae present at the time of spawning and that the individuals survived for some time. Goodrich (1933) found that individuals of Odontosyllis enopla survived swarming and considered that they might live to breed again.

In a recent paper, Green & Parke (1974) drew attention to some of the systematic problems posed by benthic members of the Haptophyceae. Particular attention was given to Ruttnera spectabilis Geitler (1942) the type species of its genus, which was shown by the fine structure of the zoids to be a member of the Haptophyceae with a characteristic rudimentary haptonema and not, as had been thought previously, a member of the Chrysophyceae (sensu Christensen, 1962). Attention was also drawn to the close similarities between R. spectabilis and Chrysotila lamellosa Anand (1937) both in the vegetative and motile phases, but no formal taxonomic changes were made pending the completion of the comparative reinvestigation of both these species together with C. stipitata Anand, the type species of the genus Chrysotila (so designated by Bourrelly, 1957).

Abereiddy Quarry is shown in Plate I. It lies at 51° 56′N, 5°13′W (Ordnance Survey Reference SM 795315), 6 km northeast of St Davids in Pembrokeshire (Text fig. 1). The quarry, a disused slate working, is surrounded by high cliffs except to the west where there is a channel open to the sea. In 1902–3, operations ceased and the quarry began to fill with fresh water and sea spray. During 1932–3 the west wall was breached to allow access to the sea so that the basin could be used as a harbour. Abereiddy is now a deep, fully saline marine basin which, at low water, is 66 m across from north to south with a surface area of 0.356 ha and a maximum depth of 24 m. In this situation it has been possible to observe sublittoral rocky sea-bed communities in an extremely sheltered area through a summer thermocline and associated oxycline. Abereiddy Quarry has previously been investigated by Bailey, Nelson-Smith & Knight-Jones (1967), who published details of the vertical distribution of Spirorbis spp. The biology of serpulid worms in Abereiddy Quarry has been the subject of continuing investigations carried out from University College Swansea (E. W. Knight-Jones, personal communication).

There are two critical stages in the life history of Laminaria hyperborea (Gunn.) Fosl. The first is the attachment of the zoospores (meiospores) to suitable rock surfaces and the second is the successful fusion of gametes. The second clearly partly depends on the first which is in turn affected by the efficiency of zoospore production by the sporophyte and the time of year that this takes place. Because of lack of information on these aspects the present study of reproduction in the sporophyte was undertaken.

In marine organisms the fresh-weight concentrations of the trace metals zinc and iron are 102–105 times the concentrations in sea water. Study of the transfer of these metals along marine food chains is of interest because of the possibility of their being pollutants of the marine environment. Also65Zn and 65Fe are released to the marine environment and have been found, in many instances, to be the predominant radionuclides in food chains leading to man (Lowman, Palumbo & South, 1957; Lowman, 1960; Osterberg, Pearcy & Curl, 1964; Preston, 1967). The transfer of these metals along marine food chains is thus of interest also in the context of human radiation exposure.

Benthic faunal communities have usually been described from data collected during a single survey, and it has been assumed that most benthic communities are reasonably stable. However, in areas such as important fishing grounds or around effluent disposal areas where surveys have been repeated periodically, the results quite frequently show marked changes. These do not always correlate to annual breeding cycles but are more unpredictable and of a different period.

Some integumental organs of Amphipoda have been briefly described by Bate & Westwood (1863). Their diagrams are extremely small and, in some cases, inaccurate. Fleminger (1973) described the integumental organs of calanoid copepods of the genus Eucalanus. He shows that these are distributed over the body in a pattern peculiar to each species. Bate & Westwood do not mention patterns in the distribution of integu-mental organs in amphipods. They do, however, describe two peculiar structures in gammaridean species of the families Talitridae and Gammaridae; they do not mention these as occurring in any other families.

‘Giant’ nerve cells have always attracted considerable interest because of the technical possibilities they offer to experimental biologists, for as well as being easy to impale with microelectrodes they can be dissected away from non-nervous tissues and used for bio-chemical analyses.

There is much variation in the form of colony assumed by the common hydroid Clava, and two forms were for long distinguished as separate species, a diffuse one found on stones and rocks in the lower part of the tidal zone and in shallow subtidal depths, with scattered polyps arising from an open hydrorhizal network of creeping stolons, and a clustered one, living on fucoid and other seaweeds in the tidal zone, with densely clustered polyps borne on a compact hydrorhizal base of very short anastomosing stolons. Johnston (1847) did not separate these forms and recognized one species only, named by priority Clava multicornis (Forskal, 1775). It was largely on the authoritative works of Hincks (1868) and Allman (1871–2) that the two forms became accepted as distinct species, the name Clava multicornis (Forskål) being adopted for the diffuse one (though Hincks admitted uncertainty in ascribing Forskål name to this) and Clava squamata (Müller, 1776) for the clustered one. More recently certain authors have considered them to be forms of one species, designated by priority Clava multicornis, but others have continued to treat them as separate species, and the question of their specific identity or distinctness cannot be said to have been resolved. Broch (1916, pp. 38–40), from a study of material from various localities, concluded that there are all transitional conditions between the two forms, rendering specific distinction impossible, and that they are evidently ecologically conditioned forms of one species. He did not, however, adduce any experimental or other evidence in support of his belief.

The haustoriid amphipods Bathyporeia pilosa and B. pelagica are common in intertidal sand deposits around the British Isles. Both species live in the surface sediments and B. pilosa is typically a high-shore species, while B. pelagica is restricted to beach levels below the high-water mark of neap tides. Gravid females are readily identified by the presence of blue-pigmented eggs held in the brood pouch where they undergo direct development. The extent of the breeding season varies with locality (Salvat, 1967; Fish & Preece, 1970) and on the west coast of Wales B. pilosa breeds throughout the year and B. pelagica from March to October (Fish & Preece, 1970). At this locality, however, the breeding cycles of the two species are similar in that they show reproductive peaks in spring and autumn and it has been suggested that the spring peak is caused by breeding of the overwintering generation, the progeny of which mature to reproduce in the autumn of the same year (Fish & Preece, 1970). In common with many amphipod species, brood size of Bathyporeia is related to body length. Salvat (1967) has shown that the brood size of B. pelagica on the west coast of France doubles from February to April, but apart from his study adequate data on brood size are lacking. This paper describes embryonic development, hatching and brood size of overwintering and summer generations of both species.

The published records of the occurrence of the Devonshire Cup Coral Caryophyllia smithii Stokes and Broderip in Scottish waters are widely scattered throughout the literature. Rees (1962, 1966) listed several of these and suggested that the paucity of records was a reflexion of the comparatively little systematic collecting that had been done on the Scottish coasts and on the continental shelf.

The purpose of the present paper is to collate and review the published records of the distribution of C. smithii and to present new data derived from extensive investigations carried out by the Institute of Oceanographic Sciences, Wormley, as part of a study of shelly faunas and sediments on the continental shelf west and north of Scotland. Additional records obtained from several other sources are also included.

The general biology of the gadoid fishes of the North Sea after recruitment to the demersal fisheries has received considerable attention, but little is known about their behaviour patterns during the period between metamorphosis and assumption of the demersal habit. In the summer of 1969 the Marine Laboratory, Aberdeen, began a series of annual midwater trawling surveys of the northern North Sea (Hislop, 1970, 1972a, b; Hislop & Bailey, 1971, 1975). During the surveys observations were also made on various aspects of the biology of the species caught. This paper describes the results of a series of trawling experiments carried out on a cruise of F.R.S. ‘Scarba’ (ex ‘Scotia’) between 12 and 29 August 1971.

Parathemisto gaudichaudi (Guerin) exists in a range of morphological forms comprising the compressa extreme, in which the fifth pereopod (P5) is only slightly greater in length than the sixth pereopod (P6), the bispinosa extreme, in which P5 is about twice the length of P6, and a complete range of intermediate forms. Other features such as the shape of the carpus and merus of the third and fourth pereopods and the shape of the uropod peduncles also vary between the two extremes. In an earlier paper on the taxonomy of the genus (Sheader & Evans, 1974) it was noted that specimens of Parathemisto gaudichaudi kept in the laboratory could moult towards either of these extremes.

This is one of a series of four papers dealing with vertical distribution of cephalopods in the North Eastern Atlantic at six stations near 20° W and at about 10° intervals from 60°N to 11° N (Clarke & Lu, 1974, 1975 a; Lu & Clarke, 1975). The present study is based upon a series of hauls made at discrete horizons between o and 2000 m with opening-closing nets during both daylight and darkness. The collections were made for the ecological programme of the National Institute of Oceanography, Wormley, Surrey, England (now part of the Institute of Oceanographic Sciences).

Hensen (,1887) drew attention to the possibility of using a pump for quantitative sampling of surface plankton and, since then, a hose-pump method has been widely used for such sampling at desired depths by Juday (1916), Lohmann (1898,1901), and Thorson (1946). A comparative study by Gibbons & Fraser (1937) suggested that such a pump had outstanding advantages over the vertical net, in quantitative work. However, Korringa (1941), working on oyster larvae, suggested that some plankton animals may be able to escape by swimming against the currents which approach the mouth of the suction hose. Brook & Woodward (1956) noticed an apparently rheotactic response shown by plankton organisms in evading water currents.

Little work on vertical distribution of cephalopods was possible before the development, in the 1960s, of sophisticated opening-closing devices usable on midwater trawls such as the 10 ft Isaacs Kidd trawl (IKMT; Foxton, 1963; Aron et al. 1964) and the series of rectangular midwater trawls developed by the Institute of Oceanographic Sciences (previously the National Institute of Oceanography) (Clarke, 1969 a; Baker et al. 1973). These developments have resulted in three papers on vertical distribution of cephalopods in the North Atlantic (Clarke, 1969 ft; Gibbs & Roper, 1970; Clarke & Lu, 1974) and one for the Mediterranean (Roper, 1972). The present paper describes the vertical distribution of cephalopods caught at 40° N 20° W, 53° N 20° W and 60° N 20° W in the North Atlantic based upon day and night series of horizontal hauls between the surface and 2000 m using the RMT combination net (Baker et al. 1973).

Cephalopod molluscs have attracted little attention as potential hosts for digenetic trematodes. Though none appears to serve as a first intermediate host, many do act as second intermediate, paratenic, or final hosts. Hence, they probably play a more important role in the life history and dissemination of Digenea in the marine environment than is generally recognized.

Previous (workers who have examined the gut contents of members of the genus Parathemisto, and who have kept and fed specimens in laboratory conditions, have concluded that they are chiefly carnivorous in habit, feeding largely on zooplankton, and to a lesser extent on phytoplankton (Conover, 1960; Baker, 1963; Kane, 1967).

The gut of P. gaudichaudi has been found to contain almost intact copepods, especially Calanus and occasionally Temora (Bigelow, 1926 – Gulf of Maine); young specimens of Euphausia superba (Hardy & Gunther, 1935 – Antarctic); and copepods (Nemoto & Yoo, 1970). Siegfried (1965 – west coast of S. Africa) found P. gaudichaudi to be a rather indiscriminate feeder, its gut contents reflecting the composition of the plankton.

Salinity is a major limiting factor in littoral and estuarine environments and the salinity encountered in such habitats fluctuates with tide, season and weather. Despite this variable situation, most investigations of salinity tolerance and osmoregulation have involved laboratory experiments at steady salinities. The literature devoted to such investigations is extensive, and has been reviewed on several occasions, notably by Krogh (1939), Potts & Parry (1964) and Kinne (1971).

The present work is part of an analysis of catches made with rectangular midwater trawls (RMTs) in the North Atlantic at about 20°W and at 60°N, 53°N, 40°N (all in Lu & Clarke, 1975), 30°N (Clarke & Lu, 1974), 18°N and 11°N (Lu & Clarke, 1975). The collections were made for the ecological programme of the National Institute of Oceanography, Wormley, England (now part of the Institute of Oceanographic Sciences).