The status of our knowledge of the organic nutrition of algae has been summarized in tabular form from time to time. Albritton (1954) listed a mere 14 taxa of pigmented algae as having been examined from this point of view. Eight of the 14 were species of Euglena and only ‘Nitzschia dosterium' (= Phaeodactylum tricornutum Bohlin) was marine. This paucity of information reflected in part the lack of suitable denned culture media as prerequisites of nutritional experiments. By the early 1960s this lack had been overcome to a large extent (see, for example, Provasoli, McLaughlin & Droop, 1957) and Thomas (1968) could list some 280 species, both freshwater and marine, on which nutritional work in terms of organic requirements had been undertaken. The vitamin requirements (or lack of them) of most of these species were known, but knowledge of their ability to grow in the dark on organic carbon sources and of their ability to utilize different nitrogen sources in the light was fragmentary. It still is, despite the fact that some of the gaps in Thomas's tables have been subsequently filled and the list of species has been extended.

There is now considerable evidence that benzo[a]pyrene hydroxylase (aryl hydrocarbon hydroxylase: AHH) is involved in the metabolism of petroleum hydrocarbons by several species of marine fish (see review by Varanasi & Malins, 1977), as well as by certain species of marine invertebrates, including crabs and lobsters (Payne, 1977). Several workers (Payne & Penrose, 1975; Payne, 1976, 1977; Bend, James & Dansette, 1977) have found increased activities of this enzyme in fish previously exposed to petroleum hydrocarbons and related compounds: similar findings have been made in a study using two species of polychaete (Lee, Furlong & Singer, 1977 a). No evidence of such enhanced activity, however, has been found in experiments with crabs and lobsters (Payne, 1977).

Many marine animals that live at depths greater than about 500 m are deeply coloured (generally red, brown, black or purple) even though there is little or no down-welling light in these regions (Clarke & Denton, 1962). The nature and function of many of these pigments are obscure. Partly, no doubt, because of the difficulty of provenance, there have been very few chemical and biochemical investigations on such pigments (see Crozier (1974) for a review of pigments in fishes). We report here an investigation of the pigments of meso- and bathypelagic medusae. The work was initiated following preliminary identification of protoporphyrin in Atolla wyvillei and Periphylla periphylla (Herring 1972): the present work confirms and considerably extends these observations (Head, 1976, M.Phil. Thesis, University of London).

There can be little doubt that competition for space, both inter- and intraspecific is a major factor in barnacle ecology. Southward & Crisp (1956) first pointed out the role of competition between Balanus balanoides (L.) and Chthamalus stellatus (Poli) in south-west Britain which Connell (1959, 1961) later demonstrated experimentally. Crisp (1958) discussed competition between the indigenous B. balanoides and the immigrant Elminius modestus Darwin in the intertidal zone, and measurements of growth rates, using manipulated populations of these two species, indicated that inter- and intraspecific competition for space after settlement is intense (Crisp, 1964).

Settlement behaviour of barnacle cyprids has been investigated extensively. There are two opposing tendencies. The cyprids settle gregariously over distances of several centimetres (Knight-Jones, 1953a, b; Knight-Jones & Stevenson, 1950; Knight-Jones & Crisp, 1953; Crisp & Meadows, 1962,1963). However, at closer range of a few millimetres they tend to space themselves out (Crisp, 1961; Knight-Jones & Moyse, 1961).

Barnacle cypris larvae, the specialized settlement stage of the life-cycle, are classical examples of larvae showing gregarious settlement. Gregarious settlement is shown when the larva is induced to settle by established individuals of its own or of a closely related species, reflecting the ability of the larva to recognize its own type, usually by chemo-tactile detection of a particular settlement inducing factor (see Crisp (1974) for review). Sessile barnacles such as species of Balanus or Chthamalus are typically hermaphrodite and gregarious settlement is of selective advantage in promoting the possibility of cross-fertilization, in addition to allowing a settling larva to identify a habitat providing all the necessary conditions for barnacle growth and development.

The glands which secrete the byssus in bivalve molluscs are located in the foot. Some glands discharge into a duct at the proximal end of the foot whilst others discharge into a ventral groove which runs forward from the opening of the duct for about two thirds of the length of the foot. In Mytilus edidis a stem or ‘rachis’ is formed by the gland which surrounds the duct (Brown, 1952). The secretions of this gland are formed into flat sheets or ribbons as a result of being discharged between numerous lamellae which occupy the blind end of the duct. The secretions are derived from two types of secretory cell. One produces large granules, packed with banded filaments, which are secreted into the crypts formed by the lamellae (Tamarin, 1975). The other produces smaller, cylindroid shaped granules which are secreted along the two faces of each lamella. The stem serves as a point of attachment for collagenous threads, produced in the groove (Mercer, 1952; Pujol, 1967 a, b) by the collagen gland which secretes globules displaying regular banding (Pujol, Houvenaghel & Bouillon, 1972). The proximal end of each thread is attached to the stem by means of a collagenous cuff, each one overlapping the previous one to form a concentric arrangement of cuffs around the stem. The distal ends of the threads are attached to the substratum by a holdfast.

A number of studies exist on the seasonal cycles of body weight and tissue biochemistry of several species of bivalve from the Clyde Sea area (Ansell & Trevallion, 1967; Ansell, 1974, et seq), including two members of the Pectinidae, namely Chlamys septemradiata (Müller) (Ansell, 1974) and Pecten maximus L. (Comely, 1974). Some comparative data are available for Chlamys opercularis (L.) from Manx waters (Soemodihardjo, 1974) and for P. maximus from the north Irish Sea (Stanley, 1967).

In earlier behavioural studies carried out at the Plymouth Laboratory, Pagurus bernhardus L. displayed no activity towards its symbiotic actinian, Calliactis parasitica (Couch) (Ross, 1960; Ross & Sutton, 1961 a). This was in marked contrast to other familiar pagurid/actinian associations, e.g. with Dardanus spp., in which the pagurid participates actively in the transfer of Calliactis to its shells (Brunelli, 1910; Faurot 1910; Ross & Sutton, 1961 b; Ross, 1970, 1974). In the case of P. bernhardus and C. parasitica, laboratory trials showed that contact of the anemone's tentacles with a shell, even an unoccupied shell or one of a living gastropod, releases a sequential behaviour pattern in which the anemone frees its pedal disc and somersaults to the shell. It has been argued (Ross, 1967) that this association exists solely because of the behaviour pattern by which C. parasitica climbs on shells.

The Phylum Chaetognatha consists of morphologically and biologically similar species and its relationship with other invertebrate groups is obscure (Hyman, 1959; Ghirardelli, 1968). The possibility of regenerative power has been investigated as one of the clues to the affinity of the phylum. Kulmatycki (1918) made cross-sectional and diagonal cuts through the body and tail fin of Spadella cephaloptera Busch and reported that this species could regenerate the whole caudal section including the body proper. Further support for regenerative ability came from Pierce (1951) who caught 26 specimens of Sagitta enflata Grassi and Sagitta helenae Ritter Zahony which appeared to be in the process of regenerating their heads (presumably lost to a large predator). He noted that the loss of this section of the body did not kill the animal. Both Kulmatycki and Pierce are cited in Hyman's (1959) important review of the phylum and headless chaetognaths have been referred to as animals with regenerating heads (e.g. Almeida Prado, 1968).

The tiny bivalve mollusc Montacuta (Tellimya) phascolionis (Dautzenberg & Fischer) belongs to the family Montacutidae, which is usually classified in a grouping of a superfamily rank, the Galeommatacea (= Erycinacea, Leptonacea or Leptonoidea) and includes many small and rather obscure species that are found associated with a wide variety of usually burrowing marine invertebrates (see Boss, 1965). M. phascolionis recently has been referred to the genus Tellimya (Chavan, 1960, 1969; Bowden & Heppell, 1968) or removed from the Montacutidae altogether and put into a new monospecific genus, Phascoliophila (Nordsieck, 1969). It is clear that a comprehensive revision of the Montacutidae is badly needed in order to establish the correct position of the present species within the family. However, the present author feels it justified in the interim to follow Ponder (1968) in recognizing Tellimya as a subgenus of Montacuta that includes the species phascolionis.

Our knowledge of the export of solids and solutes by streams from different types of catchments has lagged behind that of water yield despite the fact that it is important in the prediction of erosion and landform development as well as the prediction of water quality. To remedy this shortcoming there has developed an increasing interest in export of various substances by small catchments. Gregory & Walling (1974) have described this trend as well as our growing awareness of the need to concern ourselves with the variation of fluvial processes as a function of landform, geology and land use. But because few studies of this sort have been completed in Great Britain, Gregory & Walling stressed the need to understand the controls on sediment and solute production, particularly in a variety of different landforms and geological formations.

Infra-red images of sea surface temperature indicate that shelf sea frontal regions around the British Isles are characterized by cyclonic eddies with typical wavelengths between 20 and 40 km and growth time scales in the order of a day. A similar analysis for the shelf-break region of the Celtic Sea based on the interpretation of structures observed in infra-red sattllite images and a survey at sea shows that this region is also characterized by eddies. These eddies are usually associated with a general lowering of sea surface temperature that occurs over the shelf-break region in late summer. In this paper, observed eddy scales are compared with estimates based on theory originally developed for large-scale (3000 km wavelength) atmospheric eddies and the role of eddies in cross-frontal exchange is examined in more detail.

A numerical model of the tides in the neighbourhood of Portland Bill (Pingree & Maddock, 1977; Maddock & Pingree, 1978) indicated that there was some asymmetry in the flood and ebb tidal patterns due to the effects of the Earth's rotation. Thus, in addition to the generation of vorticity due to the bottom frictional torque which becomes large in the high-velocity shoaling region near the promontory, vorticity is generated as columns of water with planetary vorticity are stretched or squashed as they move across water depth contours.

In order to examine the Portland Bill situation in more detail, a model was developed in plane polar coordinates (Pingree & Maddock, 1979). This model allowed the flow to be taken around the promontory without the numerical difficulties associated with corners in rectangular grid meshes and gives increased resolution near the headland where the major changes in tidal structure occur. The regular geometry of the polar model also allows the use of an idealized submarine topography and therefore changes in tidal flow due to imposed beach gradients can readily be examined.

The polar model has now been developed to derive the tidal flow around an idealised circular island surrounded by a uniformly sloping beach gradient. In the absence of effects due to the Earth's rotation the derived tidal structure and the associated patterns of residual flow possess twofold symmetry. In a rotating reference frame, however, some asymmetry in these flow patterns can be detected. In this paper some numerical results showing the hourly tidal streams around an island are derived.

The early qualitative works on the harpacticoid fauna of the British Isles by T. & A. Scott, Norman, Brady, Gurney and Thompson largely omitted the intertidal psammic biotopes. Nicholls (1935, 1939) did much to redress the situation, describing many new species of interstitial harpacticoids from the sandy shores of the Firth of Clyde. Although his studies were taxonomic, he supplied some useful information on the distribution of the species. Some ecological data is also to be found in subsequent works on the east coast of Ireland (Wells, 1963 a; O'Riordan, 1971), the Exe estuary (Wells, 1963 b) and the Isles of Scilly (Wells, 1961, 1970). The only detailed studies of interstitial harpacticoid zonation on British coasts are those of Harris (1972) for the lower shore at Whitsand Bay, Cornwall, and Mclntyre & Murison (1973) for Firemore Bay, Scotland.

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).

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).

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.

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.

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.