Large catches of the snake blenny, Lumpenus lampretaeformis, have been made in the inshore waters of the west coast of Scotland. Analysis of these catches confirm the view that this species shows marked seasonal variations in abundance. The species lives for up to 9 years and has a rapid growth rate in the first 2 years. It feeds mainly on meiobenthic organisms, of which polychaetes, harpacticoid copepods, ostracods and nematodes are the most important. The reason for the seasonal variation in catch rate is discussed and it is speculated that it may result from the fossorial habit of the adults and the parental care of the eggs.

Amongst Gunnar Thorson's concluding remarks in his review on marine-bottom communities (Thorson, 1957) he noted that a sequel to the study of macrobenthic parallel communities should be a detailed analysis of the meiobenthos and microbenthos within these communities, adding that the work by Remane and his collaborators in shallow water and on beaches in Kiel Bay indicated that the meiobenthos is likely to show a pronounced uniformity within these communities. Many qualitative sub tidal meiobenthic surveys have followed (e.g. Gerlach (1958) for the nematodes; Por (1964) for the copepods) but it is only very recently that wide-scale quantitative work of the type pioneered by Petersen (1913) for the macrofauna has been applied to the meiofauna (Drzycimski (1969) and Soyer (1970) for the copepods; Ward (1973) and Tietjen (1977) for the nematodes). Around the coasts of Great Britain the only subtidal meiobenthic survey is that by Ward (1973,1975) of the nematode genera of Liverpool Bay, although quantitative faunal and environmental data are available for a number of sublittoral stations (Mclntyre (1964) and Wells (1965) for muddy deposits in Loch Nevis and the Fladen North Sea ground; Warwick & Buchanan (1970) for fine sand and silt deposits off the Northumberland coast; and Mclntyre & Murison (1973) for shallow fine sand in Firemore Bay).

A species believed to be more primitive than C. natans (Grontved) (type species of Calliacantha Leadbeater) has been described and illustrated by means of light and electron microscopy of dry whole mounts prepared in situ from freshly gathered sea water, mainly in South Africa but supplemented by one gathering from Britain.

In the Acantharia, two different symbiotic algae are known. One is a dinoflagellate with a typical mesocaryon and the other, studied here, exhibits the characters of the Prymnesiophyceae (Haptophyceae).

Detailed descriptions of the non-motile and presumed premotile stages of this symbiont are given, with special reference to the haptonema, the scales and the plastid.

Comparisons are made with other members of the Prymnesiophyceae and the systematic position of the symbiotic alga is discussed.

The Priapulida phylum is a rather homogeneous small group of marine invertebrates, living buried in sand and mud of cold waters. These worms present great difficulty in determining their systematic position: in the first instance, Priapulida were considered to be pseudo-coelomates, and classified among the Aschelminthes (Hyman, 1951). How ever, later studies (Shapeero, 1961) have pointed out that the body cavity is actually a coelom, and not a pseudo-coelom. Consequently it seems improper to include Priapulida among Aschelminthes, even if their real position still remains undefined. Today most authors tend to consider priapulids as the last relicts of an originally larger group, forming a separate phylum (van der Land, 1970). We can assume some connexions with other minor Protostoma, but not to an extent sufficient to consider a possible group affinity (Grassé, 1959). The general anatomical organization of a priapulid is now well known (van der Land, 1970), but the only detailed microscopical descriptions are those of the genus Priapulus (Mattisson, Nilsson & Fange, 1974) and the genus Tubilucus (Kirsteuer & van der Land, 1970). We have only incomplete data and summary descriptions concerning the other existing genus. Ultrastructural researches are even more scarce; electron microscope studies could clarify the submicroscopical organization of these animals and allow comparisons with other groups. Afzelius & Ferraguti (1978), for instance, have shown that the sperm of Priapulus caudatus present a very primitive pattern, resembling that of the sperm of many other marine invertebrates with external fertilization. The muscular systems are also useful for researches of phylogenetic correlations: it is, in fact, possible to correlate the ultrastructural organization of the muscles with the systematic position of their respective animals (Hanson & Loewy, 1960; Lanzavecchia, 1977). For the muscular systems of priapulids the only pertinent data are those of Mattisson et al. (1974) on Priapulus caudatus. A detailed analysis of the muscles of other species seems therefore necessary to set up a general picture of the situation in Priapulida. In these animals the muscles are organized to form a typical hydraulic system. The hydraulic systems present one of the most topical problems, from both the morphological and functional points of view (Hammond, 1970; Chapman, 1975).

In order to gain a general understanding of the problems of fish locomotion and appreciate them in an evolutionary context, it is important that we have information available on the kinematics, hydrodymamics and energetics of the swimming of as wide a range of fish as possible. At present, most of our knowledge of fish locomotion is restricted to the swimming of streamlined, pelagic and nektonic teleosts, capable of high speeds and accelerations, that are either neutrally buoyant or have a buoyancy close to neutral (see Lighthill (1969), Webb (1975), Bone (1975) for reviews).

Sodium orthovanadate added internally is a powerful vasoconstrictor in perfused, irrigated gills of Anguilla anguilla. The anion is active at concentrations as low as 10-7 M and its action is antagonized by β-adrenergic vasodilators such as adrenaline and isoprenaline. These effects are discussed in terms of the known mode of action of vanadate as an inhibitor of (Na+ + K+)-dependent ATPase. The biological and pharmacological effects of naturally occurring vanadate are assessed.

Two benthic Rhodophyta, Ceramium pedicellatwn and Neogardhiella baileyi, were cultured in the laboratory to investigate uptake and subsequent release of Cu by both living and decomposing thalli. Concentration factors of Cu in the thalli of 4540-6864 were obtained. Algae grown initially in copper-supplemented media were cultured for 7 days in organic free medium and the amounts of Cu associated with the dissolved inorganic and organic fractions were then determined.

The general morphology of the antennary and maxillary glands, which form the major renal system of adult Crustacea, has been described and reviewed by Goodrich (1945). However, studies on the fine structure are restricted mainly to the antennary glands of decapods, including Orcotiectes sp. (formerly Cambarus sp.) (Anderson & Beams, 1956; Beams, Anderson & Press, 1956), Orconectes affinis (Kümmel, 1964), Procambarus clarkii (Miyawaki & Ukeshima, 1967; Schaffner & Rodewald, 1978), Procambarus blandingi (Peterson & Loizzi, 1974), Austropotomobius pallipes pallipes (Riegel & Cook, 1975) and Uca mordax (Schmidt-Nielsen, Gertz & Davis, 1968). The maxillary gland of Artemia salina is the only excretory system of a non-decapod which has been studied in detail (Tyson, 1968, 1969a, b). Morelli & Tobolla worked independently on the antennary glands of amphipods, Gammarus sp. (cited Kümmel, 1973), but their studies were restricted to the site of filtration.

The seasonal variations of dissolved inorganic and organic N and P in the waters of the English Channel during an 11-year study are discussed. The N results show that as NO3 is utilized by phytoplankton there is an increase in the concentration of the dissolved organic N fraction and there are always significant amounts of dissolved N in some form in the water.

Mediomastus Hartman (1944) is a genus of capitellid polychaetes with ten species of which only M. fragilis, described from the Danish Isefjord by Rasmussen (1973), has been found in European waters. In 1963 Clark & Dawson recorded the presence of an incomplete specimen of a capitellid from the west coast of Scotland and tentatively assigned it to Mediomastus. However, collections made by Dr P. E. Gibbs (Marine Biological Association, U.K.) in the Shetlands during April 1974 revealed a large number of capitellids subsequently identified as fragilis. More recently M. fragilis. has been recorded in large numbers during sampling programmes carried out by Dr A. Walker (Marine Science Labs., University College of N. Wales, Menai Bridge) in Dublin Bay and Liverpool Bay, and Mr J. Hunter (Highland River Purification Board, Dingwall, Ross-shire) has collected specimens from Dornoch Firth and Cromarty Firth, Easter Ross.

Moreau (1876), Bohr (1894), and Fänge (1953) are among those authors who have demonstrated that the swimbladder walls of certain fish are highly impermeable to gases. This property assists in the maintenance of high partial pressures of gases in the swim-bladder and enables physoclist fish to use the swimbladder as a buoyancy mechanism, often at great depth. It has been shown experimentally that the swimbladder contains a high percentage of oxygen (Fänge, 1953; Kanwisher & Ebeling, 1957) and that this percentage increases with depth in most fish (Scholander & Van Dam, 1953; Scholander, 1954). Diffusion of gas through a tissue increases with increasing partial pressure difference across the tissue (Krogh, 1919). This may be as high as 10–20 atm in inshore gadoids such as the saithe, Pollachius virens (L.) or 50–60 atm in mesopelagic fish (Kanwisher & Ebeling, 1957). Thus low permeability to oxygen is required if the swimbladder is to be used as a buoyancy mechanism at any depth.

The small acoele Convoluta roscoffensis Graff occurs locally in abundance in suitable intertidalareas of wet sand from the Channel Islands and the coast of Brittany southwards along the westcoast of France (Holligan and Gooday, 1975). The species is well known for its uniquely intimate symbiosis with Platymonas convolutae Parke et Manton: after initial ingestion of the living alga by hatching ‘ white’ worms the animal comes to depend entirely on the algal cells contained in its tissues for its nutrition (Holligan and Gooday, 1975).

Eggs of the capelin, Mallotus villosus, are laid superficially on sandy beaches where they may be exposed to temperatures below –5 °C during tidal emersion. The eggs do not freeze until the temperature of their surroundings falls to a mean of –11.9 °C for eggs at the late blastula stage and –10.6 °C for eggs about to hatch, even though films of sea water covering the eggs are frozen. Newly hatched capelin larvae freeze at a mean temperature of –2.5 °C when the sea water surrounding them freezes, and are probably supercooled at temperatures below this before hatching. Evidence is presented which demonstrates that capelin eggs survive low temperatures by supercooling, and that they can do so in the presence of external ice crystals because the chorion prevents ice penetration and hence seeding of the eggs' internal fluids. The chorion of Mallows is shown to possess an extra secondary layer, like that of the related smelts. The primary function of this outer layer appears to be be concerned with adhesion to sand grains but it seems likely that it also prevents or delays ice penetration.

In most demersal and some pelagic marine fish O- and I-group stages are found on inshore nursery grounds which are often situated in coastal indentations and estuaries

where flushing rates are low and the build up of persistent pollutants can be correspondingly high. Their movements are restricted, only leaving the nursery areas towards the end of their second year (Lockwood, 1974; Riley, 1973). This, coupled with the fact that juveniles may be more susceptible than adults to pollutants, makes them particularly vulnerable to the potential hazards of inshore pollution.

The physico-chemical properties of most trace metals, however, generally preclude their occurrence at high concentrations in sea water itself. Instead, most of the metal is transferred to the particulate phase of the water mass and to sedimentary reservoirs (Renfro, 1973) so that concentrations of metals in sea water very rarely reach levels which are known to be acutely toxic to fish. The main risk from direct effects of metals lies in poisoning resulting from internal accumulation.

Little information is available on metal concentrations occurring in young fish. Hardisty et al. (1974) and Hardisty, Kartar & Sainsbury (1974) have examined zinc, cadmium and lead levels in O-group and older flounders from the Bristol Channel. Andersen, Dommasnes & Hesthagen (1973) found high concentrations of zinc in O- and I-group herring and sprat from Oslo Fjord, Cross & Brooks (1973) reported on manganese, iron and zinc concentrations in juvenile estuarine fish. Pentreath (1973 b) has reported on zinc concentrations in the organs of I-group plaice.