Three surveys were made in 1963 and five in 1964 in the area of the English Channel between the English and French coasts and between 3° 40' W and 5°10' W. This area had been surveyed in 1961 and 1962. Temperature and salinity were determined at o, to and 50 m and phosphate silicate and nitrate at 10 and 50 m. The results are presented graphically. Temperature and salinity were compared with Lumby's 25–year averages. The year 1963 started with unusually low temperatures and salinities higher than average. Temperature remained low in the spring, but salinity decreased. The year 1964 started with temperatures and salinities above normal, but during the rest of the year values were close to average. Nitrate in January 1964 was higher than in January 1963. Analyses of suspended matter at 12m were made for carbon, nitrogen and phosphorus on most surveys, and mean values for the whole area are given. Suspended carbon was 67 /ig C/l. in January 1963 and 51 /*g C/l. in January 1964, a significant difference. Increases in sus-pended carbon, nitrogen and phosphorus were found in spring and summer 1964.

Analysis of the carotenoid pigment and lipid concentrations of groups of the smaller zooplankton organisms from different depths has suggested a midwater maximum for carotenoid concentrations and a slight depth-related increase in lipid content. Similar analysis of seventeen species of euphausiid has not indicated similar trends, but has shown a close relationship between size and pigment content in all species other than those of Stylocheiron, which have significantly lower pigment concentrations. Comparisons of the data of Fisher, Kon & Thompson (1964) on the pigment and lipid concentrations of copepods with the known depth ranges of the various species have suggested a midwater maximum in pigment concentrations, but no consistent trends in the lipid concentrations. A midwater pigment peak is explicable in terms of pigment accessibility and requirement for protective coloration, and the significance of the pigments is discussed.

Mortality resulting from fishing of scallops (Pecten maximus L.) can be divided into the loss caused by their removal for marketing and the indirect damage inflicted during the operation both by the dredges on the sea bed and the rough handling of undersized discards on board the boat (Medcof & Bourne, 1964; Caddy, 1968). Direct fishing mortality is easily measured if both the relevant biological information and catch data are available. Indirect fishing mortality is more difficult to estimate. Deaths due to damage by the dredges cannot easily be distinguished from natural deaths, and although damage to discards can be assessed before they are thrown back (Medcof & Bourne, 1964), the correlation between such damage and subsequent mortality is almost impossible to obtain in the field.

An initial report is presented on some chemical properties of the waters in the Tamar Estuary. The results are compared to those obtained in the Western Channel during the same period. Considerable differences are shown in the concentrations of inorganic nutrients but the dissolved organic nitrogen concentrations are relatively similar. Dissolved iron has been estimated both before and after the breakdown of organic compounds by photocombustion. The results show the build-up of humic substances and associated iron after heavy rain. When the concentration of suspended sediment in the water is high it can control the level of dissolved phosphorus by removing it from rich water and releasing phosphorus into poor waters.

Adult males of Nereis virens (Sars) spawn while swarming in mid-water and show epitokous changes which include enlarged parapodia, natatory chaetae and histolysis of the body wall. Females spawn while in their burrows and do not show such changes. An artificial rise in temperature can induce premature spawning. Seminal fluid is ejected through pygidial pores, but no such pores occur in the female. Both lunar period and temperature rise seem to be involved in initiating spawning, which generally occurs in early May in the Thames populations. Gravid worms show a peculiar method of swimming in which the anterior region is held rigid. A pair of flagellar vanes and other features characterize the fine structure of the spermatozoon. The mature oocytes bear microvilli, and some express a jelly-like layer after fertilization which traps excess spermatozoa. Many unit-membraned vesicles, of uncertain function, occur in the periphery of the nucleus of the mature oocyte. At fertilization the acrosomal contents are discharged on to the surface of the oocyte. The structure and behaviour of the monotrochophore, trochophore and nectochaete larvae, and the details of the nature and rate of development of such structures as the parapodia, cirri, palps and jaws, differ in some ways from the known larval development of certain other nereids. A very brief planktonic phase occurs in larval life, and young worms migrate from the sublittoral to the littoral regions.

Typically, adult digenetic trematodes are found as parasites of vertebrates, but Freeman & Llewellyn (1958) described sexually mature, unencysted digeneans from the kidney region of the mud-dwelling lamellibranch Scrobicularia plana (da Costa) collected from Chalkwell, near Southend-on-Sea, in the Thames estuary. The trematodes were identified as belonging to the genus Proctoeces (Odhner, 1911) and of the family Fellodistomatidae, subfamily Haplocladinae (Odhner, 1911). Freeman and Llewellyn considered that the features exhibited by the specimens were consistent with the description for Proctoeces subtenuis (Linton, 1907) Hanson, 1950, a species which had been recorded up until that date only as a parasite of the hind gut of marine teleosts belonging to the families Labridae and Sparidae from the Red Sea, New Zealand and the eastern seaboard of America.

Monthly sea temperatures are tabulated for Station E1 from 1960 and for Plymouth Sound from 1958. The 70-year series now available shows that annual means increased by 0·75°C up to the 1950s. Since 1960 inshore temperatures have fallen 0·5°C and E1 surface temperatures 0·4°C. Sea-bottom temperatures at E1 increased 0·4°C between 1920 and the 1950s, and have fallen 0·4°C since 1960. The changes have been most marked in the second half of the year, but the last quarter (October-December) is still somewhat warmer than in 1920 and earlier.

Precocious development of sexual reproductive structures (sporosacs) in Cordylophora (Pallas, Allman) occurs when colonies are grown in the absence of a suitable substratum. Neither varying the nature of the substratum provided nor diverse surgical manipulations will induce this morphogenetic modification. Sessile colonies will also initiate sporosac development if ubstrate availability is limited experimentally.

The genus Chrysochromulina Lackey (1939) comprises a number of golden-brown flagellates now included in the class Haptophyceae {sensu Christensen, 1962, 1966). So far 21 species have been described and their scale morphology and fine structure are well documented.

The permeability properties of the silvery walls of the swimbladders of eels (Conger conger and Anguilla anguilld) have been studied. The intact swimbladder wall is very much more impermeable to carbon dioxide, oxygen and nitrogen than ordinary connective tissue. Removal of the silvery layer of the wall, which contains crystals of guanine with a little hypoxanthine, increases the permeability about 100 times and leaves a transparent ‘epithelial’ layer only a little less permeable than connective tissue to these gases. The wall of the pneumatic duct of the conger swimbladder, which is not silvered, has permeability properties similar to those of connective tissue. In long-lasting experiments a production of carbon dioxide not coupled to oxygen usage was detected in the epithelial layer. The ratios between the diffusion constants of CO, N and O for both the silvery and epithelial layers show that diffusion probably takes place through water-filled pathways, and calculations show that impermeable overlapping crystals embedded in the silvery layer could account for its very low permeability. Two deep-sea eels were shown to have swimbladders whose walls contained about 10 times more guanine/unit area than the conger eel. The possibility that layers of guanine crystals may divide fish into compartments is discussed.

Rich assemblages of acid-resistant microfossils occur in intertidal sediment from the British Isles and are here reported, for the first time, to contain large numbers of dino-flagellate cysts. These cysts provide evidence to show that the distribution of certain dino-flagellate cysts is different from that of the motile stage, that the coastal distribution of cysts appears to be controlled by currents and that their occurrence within bays is possibly related to localized temperature and salinity conditions. Further, they present evidence that potential conditions for a red tide of Gonyaulax polyedra Stein may be present in the east Irish Sea.

Artemia salina has been reared on unialgal diets of Phaeodactylum tricornutum, Monochrysis lutheri, Platymonas tetrahele and Chlamydomonas sp. In most instances the component fatty-acid distribution of the Artemia bore little resemblance to that of its food. Thus, oleic and stearic acids are relatively enriched in the shrimps, whereas hexadecatetraenoic acid is much depleted. It is suggested that the metabolic requirements of the shrimps is of at least equal importance to the composition of their food in determining the component fatty-acid distribution of their lipids.

The features and history of a poikilohaline lagoon near Titchwell, Norfolk, England, are described and its invertebrate fauna (recorded between 1959 and 1970) is listed. The list includes 44 species new to the lagoon since 1959 (26 species new to the Scolt Head region and four species new to Norfolk). It is considered that the fauna is of the relict type, perhaps representing what remained of a former salt-marsh fauna together with some marine species. Notes are included on the biology and geographical ranges of several species which are rare or have imperfectly known distributions in Britain. The records of five particular species are believed to represent the northern limits of these animals on the east coast in 1971, when Titchwell Lagoon was drained, destroying the fauna and flora.

The activity of the following planktonic animals has been observed at hydrostatic pressures up to 500 atm: Gigantocypris mülleri, Conchoecia hyalophyllum, C. macrocheira, C. rhynchena, Parathemisto sp., Megacalanus longicornis, Euaugaptilus magna, Pareuchaeta gracilis, Pleuromamma robusta, Anomalocera patersoni, Euphausia krohni, Acanthephyra pelagica and Amalopeus elegans. Respiration of Gigantocypris and Systellaspis debilis was also measured at pressure.

The polychaete Polyphysia crassa (Oersted) is unusual in possessing a well-developed body-wall connective-tissue layer which exceeds the combined thickness of the circular and longitudinal muscles. Both collagenous and elastic fibres are present in this layer. The collagen is organized as a loose three-dimensional lattice allowing longitudinal, circumferential or radial distension of the body wall and, as in other soft-bodied invertebrates, serves the functions of providing a base on which the muscles can act and of imposing limits to the extensibility of the system. The elastic fibres are organized as an apparently randomly oriented meshwork of stout fibres around the circular muscle blocks and are attached to both the circular and longitudinal muscles. Columns of elastic fibres extend radially from the supramuscular coarse meshwork through the ‘holes’ in the collagen lattice to the epidermal basement membrane. As the elastic columns extend outwards the fibres become finer and more numerous and flute out to give a wide area attachment to the epidermal basement membrane. The radial elastic columns are cross-linked by tangential elastic fibres. Although at any point the main collagen and elasticfibre bundles are oriented at right angles to one another, collagen fibres are invariably associated with the elastic fibres and the two fibre types form a single functionally inte-grated system. Polyphysia lives in flocculent, sublittoral muds and the burrowing mechanism employed involves a pronounced direct peristaltic wave of simultaneous circular and longitudinal muscle contraction which necessitates considerable radial thickening of the body wall. The functions of the elastic fibres appear to be to oppose the radial distension of the body wall which the collagen lattice permits and to control the folding of the cuticle and epidermis and the return of the collagen system after the passage of a peristaltic wave.

The abundance of gastropods characteristic of rocky shores throughout the world (Southward, 1958) has encouraged investigation of their ecology and behaviour in several areas, although studies under laboratory conditions seem to have been restricted largely to the common European species Littorina littorea and Patella vulgata. Most investigations of littorinid behaviour have concentrated upon their response to light and gravity (see Newell, 1958, for a critique of earlier work), as the most important factors, after exposure, to influence life upon the shore. Variations in salinity are also significant, however, and ecological observations make it clear that littorinids are able to withstand a considerable range of salinity (Moore, 1958; Fretter & Graham, 1962; Newell, 1964; Green, 1968). But ecological studies alone do not necessarily reveal whether this capacity is to resist an adverse environment by a period of inactivity or, more particularly, to retain activity within a wide salinity range; nor do they show how far the potentialities of particular populations are related to the conditions under which they actually live. Examination of this aspect has been undertaken with L.littorea on the Atlantic coast of Canada (Gowanloch & Hayes, 1927) and with L.knysnaensis Philippi and other prosobranchs in False Bay, South Africa (Broekhuysen, 1940). However, these studies were restricted to determination of limiting salinities, without consideration of the extent to which activity occurred within the range of tolerance of the species concerned. Investigation of salinity tolerances in L.littorea is also of some general interest since, as pointed out by Newell (1958), the behaviour pattern of this species is probably fairly typical of the more mobile intertidal invertebrates.

The second recorded specimen of Stygiomedusafabulosa Russell was taken in June 1971 from 1200–1400 m in the Bay of Biscay, near the area in which the first was caught. The similarity of the two specimens of S.fabulosa suggests that Stygiomedusa stauchi Repelin, described from a single specimen taken near the Congo estuary, is a distinct species.

Some preliminary experiments are described which indicate that the larvae of Scrupocellaria reptans (L.), Spirorbis corallinae de Silva and Knight-Jones forma reptans l'Hardy and Quiévreux and Spirorbis (Janua) pagenstecheri Quatrefages prefer to settle on the younger parts of the fronds of Laminaria digitata (Huds.) Lamour. Two possible explanations for the ecological significance of this behaviour are discussed and some supporting evidence is given.

Luidia ciliaris (Philippi) has intraoral digestion and was found to be a selective feeder on echinoderms. In 258 specimens from the Irish Sea, echinoderms occurred in 97·4% of all stomachs containing food and contributed 92% of the food volume (estimated by points method). The most important food items were Psammechinus miliaris, Ophiothrix fragilis, Ophiura albida and Ophiocomina nigra. Ophiocomina nigra did not occur as frequently as would be expected from their availability. Observation in situ revealed that large specimens had efficient escape response to moving Luidia and aquarium experiments showed that O. nigra deprived of their moving ability were readily eaten. However, the Luidia showed clear preference to Ophiothrix fragilis. There was no distinct seasonal difference in the composition of the diet, but a tendency to a minimum feeding activity in May-June, probably connected with the spawning period.

Methods are described for rearing turbot (Scophthalmus maximus L.) and brill (Scophthalmus rhombus L.) to late larval stages; the major part of the work was done on the former species. Turbot were reared to 16–0 mm and brill to 17–0 mm in length. Rearing tanks ranged in capacity from 8 to 60 1. Turbotlarvae hatched at 2–7–3–0 mm and successful first feeding was established on rotifers (Brachionus plicatilis) at a length of 3–6–3–8 mm; larvae were transferred to a diet of Artemia nauplii at 5–6—6–0 mm. Experiments on the effect of temperature on growth and yolkabsorption rates in yolksac turbot larvae showed optimal growth efficiency at 15–0 °C. Delayed initial feeding reduced subsequent survival. Drawings of larval development of turbot and brill were made as an aid to their identification in plankton samples.