Studies were made relating to the problem of how Calanus feeds during winter in the Clyde sea-area. Different diets were assessed in terms of sustaining the levels of body nitrogen and phosphorus in Calanus helgolandicus (Claus) over a period of several days. The test diets, all equivalent to the same level of particulate nitrogen in sea water, were: (1) suspended matter collected from the Clyde sea-area in winter; (2) particulate material produced in a foam-tower by bubbling sea water enriched with soluble extracts of plant cells; (3) living nauplii of the barnacle Elminius modestus Darwin; (4) dead nauplii of this species.

It was found that neither body nitrogen nor body phosphorus was sustained by diet 1; that body nitrogen, but not body phosphorus, was sustained by diet 2; that both were sustained by either of diets 3 and 4.

With living Elminius nauplii as the food, each Calanus captured the equivalent of 25 % of its body nitrogen and 47·3 % of its body phosphorus daily: with dead nauplii as the food the corresponding values were 34·4 and 44·5%. These rations are much higher than those found in an earlier study of Calanus grazing on a spring diatom increase in the Clyde (Butler, Corner & Marshall, 1970) and demonstrate that animal diets are readily captured.

In general, the results indicate that Calanus could survive the winter in the Clyde sea-area by feeding carnivorously.

The Monstrilloida form an aberrant group of Copepoda, distinguished by the complete lack, in the adults, of gut and mouth-parts. Sars (1921) divided the group into two sections, one being the Monstrilloida Cyclopimorpha, comprising a single family, now called the Thespesiopsyllidae (see Wilson, 1932), with two genera. The larvae of Thespesiopsyllus are gut parasites of ophiuroids (Bresciani & Liitzen, 1962). The second genus, Orientopsyllus, was described by Sewell (1949) from the Indian Ocean.

The second section, the Monstrilloida Genuina, comprises the single family Monstrillidae, various authors (Malaquin, 1901; Sars, 1921; Rose, 1933; Davis, 1949) differing in their division of this into genera. The present author regards the family as consisting of three genera, Monstrilla Dana, 1848, Thaumaleus Kroyer, 1846, and Monstrillopsis Sars, 1921, separated according to the criteria listed in Table 1.

A bloom of the dinoflagellate Gyrodinium aureolum Hulburt in the eastern Irish Sea during September and October 1971 was accompanied by unusual mortalities of Arenicola marina L. and Echinocardium cordatunt Pennant. Observations in the field and laboratory suggest that the mortalities may not have been directly related to the occurrence of Gyrodinium but could have been a consequence of unusual climatic conditions which resulted in oxygen depletion in benthic substrates. The decomposition of the bloom possibly aggravated the situation.

The current interest in diversity as one of the major parameters describing a community has led to an increasing number of published results and theoretical discussions during the last years. Diversity has variously been related to other attributes of the community or properties of the environment, among which time, spatial heterogeneity, stability, primary production, productivity, competition, predation, niche structure and evolution. Although this rather overwhelming amount of possible relations seems somehow too much of a good thing, the importance of diversity remains well established in current ecological theory. One of the most important applications of diversity indices is their usage in the biological assessment of pollution. This immediately raises the problem of comparing diversity indices within habitats in time or between habitats in communi-ties. These comparisons are frequently made, yet the statistical significance of the observed differences or similarities is seldom mentioned. A test for these differences was formulated by Hutcheson (1970) but it apparently failed to attract the attention it deserves. In this study it was our purpose to investigate the distributions of the more important diversity indices and their evenness components in a low-diversity community of meiobenthic copepods of a shallow brackish water pond in northern Belgium. In this habitat the number of species is rather low, which greatly simplifies the analysis, and we hope that the statistical behaviour of the indices we find will hold for other, especially other low diversity communities as in polluted environments, as well. We chose copepods because they are taxonomically well known, the benthos because it is approximately two-dimensional and a shallow environment because of the possibility of accurate sampling.

Specimens of Golfingia margaritacea (Sars) (Sipuncula) from the south coast of Devon and Cornwall and from Raasay, West Scotland, are described and discussed in relation to the taxonomy and zoogeography of the species.

A number of procedures are now available for calculating the effects of ionic inter-actions on the behaviour of solutions as complex as sea water (Whitfield, 1973 a). These procedures are able to give a good account of the properties of the major electrolyte components (Leyendekkers, 1973 a; Robinson & Wood, 1972; Whitfield, 19736) and of the colligative properties of sea water (Robinson & Wood, 1972; Whitfield, 1973 c, d). However, greatest interest centres around the possibility of predicting the effects of these major components on the multitude of ionic equilibria that influence the properties of the less abundant constituents that are of greater biological and geological importance. It is here that the newer approaches to marine chemistry are weakest because suitable thermodynamic data are lacking. One system of practical importance that can be studied using a variety of theoretical approaches is the acid ionization of ammonium ions represented by the equation The toxicity of ammonium salts to freshwater life has been shown to be strongly dependent on the pH in a manner that is consistent with un-ionized ammonia (NH3) being the most lethal fraction (see, for example, Wuhrmann & Woker, 1948; Downing & Merkens, 1955; Lloyd & Herbert, i960; Hemens, 1966; and Brown, 1968). These papers and many others have been thoroughly reviewed (EIFAC Technical Paper no. 11, 1970, Kemp, Abrams & Overbeck, 1971). The free base (NH3) has a relatively high lipid solubility because it carries no charge and is therefore able to diffuse quite readily across cell membranes (Fromm & Gillette, 1968).

The question of how organisms living below 1000 metres depth in the oceans obtain food in sufficient quantity to survive has lately received a lot of attention (Vinogradov, 1968; Sanders & Hessler, 1969; Fournier, 1972). The oldest and simplest theory, first advocated by Agassiz (1888), is that deep-sea organisms are nourished by a ‘rain’ of organic detritus from overlying surface waters. Detritus is defined to include all organic particles, living and dead, which sink passively. An alternate proposal by Riley (1951), Vinogradov (1962) and Wickstead (1962) is that the main supply of food for deep-sea plankton is conveyed from the euphotic zone by overlapping vertical migratory plankters.

Pilchard eggs were collected over a grid of 30 stations visited on 14 cruises from August 1969 to November 1970. The samples were taken with oblique tows of a 1 m terylene net at 4 knots, the average volume of water filtered being 750 m3. The formalin preserved eggs were graded into the series of stages described by Gamulin & Hure. No very early eggs were found, but from the occurrence of stage 2 eggs it is deduced that most spawning takes place in the early hours of darkness, between 20.00 and 24.00 h B.S.T.: some spawning must also occur all round the clock.

There were two main peaks of spawning, June-July and October-November, when large numbers of eggs were found inshore; the average numbers reached 196 per m2 water column in July and 30 per m2 water column in October. Smaller numbers of eggs were taken in the other months of the year, mostly offshore, and with a minimum in December–February. In the spring (March-May) the area sampled was well clear of the main area of spawning of pilchard in the approaches to the Channel, north or northwest of Ushant.

During the peak months no particular part of the sampling area appeared to be especially favoured for spawning.

The significance of the two main peaks of spawning is discussed in relation to the problem of recruitment of fish to the population. As an alternative to the accepted hypothesis that young pilchard move back to the Bay of Biscay for maturation it is suggested that some of them, at least, may survive and mature in the Channel.

A study of the dissolved inorganic salts of nitrogen, silicon, phosphorus and carbon and their particulate forms in the Bristol Channel (Abdullah, Dunlop & Gardner, 1973) has shown that the primary sources of these elements are run-off and waste disposal. Furthermore, the slow flushing rate of the Channel plays an important role in the accumulation of these materials in the eastern part. An important constituent of run-off is the heavy metal load especially in industrial waste. Some preliminary investigations (Abdullah, Royle & Morris, 1972; Butterworth, Lester & Nickless, 1972; Nickless, Atenner & Terille, 1972; Preston, 1973) have shown that certain trace metals such as Cu, Pb, Cd, and Zn are added to the Channel in sufficiently large quantities to produce high concentrations not only in the waters of the Severn Estuary and Swansea Bay, but also in the local fauna.

There is increasing evidence that the specific growth rates of phytoplankton are hyperbolically related to the intracellular concentrations of rate-determining nutrients by expressions of the Michaelis-Menten type used in the study of enzyme reaction kinetics (see, for example, Caperon, 1968; Droop, 1968; Davies, 1970; Paasche, 1973). This has led us to inquire whether there might also be relationships, analogous to those which describe the effect of inhibitors upon the rates of enzyme reactions (Dixon & Webb, 1958) which can be applied to the growth of phytoplankton in the presence of sublethal levels of toxic substances.

Factor analyses have been carried out on the total data for 134 planktonic forms sampled during the 1965 SOND cruise by R.R.S. ‘Discovery’. Species assemblages are largely consistent with the intragroup analyses carried out previously (Angel & Fasham, 1973). Factor score plots for the separate day and night series confirm the rather limited number of categories of vertical distribution patterns that occur despite the occurrence of vertical migration. The analysis of the combined day and night data confirms the rather limited number of patterns of vertical migratory behaviour. Size spectra of euphausiids in some of the assemblages associated with each category suggest that there may be resource partitioning. The trophic relationships within the assemblages appear to be structured and are discussed in the light of the limited knowledge of the feeding behaviour of many of the species involved. Diurnal vertical migration behaviour in planktonic species appears to be limited to the top 700 m.

A range of 62 species of marine fishes representing 34 families was examined for the presence of parasitic copepods. Forty-one species were found to harbour 39 species of copepod belonging to 9 families. The remaining 21 species of fishes were not infected. The incidence and intensity of infection were recorded and these provided material data on the host-parasite relationships. The site of infection and the developmental stage of the parasite were also recorded. The frequency distributions of number of copepods per host were calculated for Clavella adunca and Bomolochus confusus. The age of the host was shown to influence the frequency distribution of Bomolochus confusus. The host specificity of the copepod species was analysed and 70 % of the species were found to be specific for one host species or for different species of the same genus.

In 1908 Lohmann described a small dinoflagellate which appeared to lack a sulcus and was therefore placed in a new genus – Protodinium. The type species, P. simplex (Text-fig, IA) was broadly ellipsoidal with broad rounded apices, circular in cross-section and about 1–5 times as long as broad. The girdle was poorly defined, but was more or less median in position. The nucleus was relatively large and centrally located and yellow leaf-life chloroplasts, four to many in number, were arranged in the periphery of the cell.

Regeneration of ectoderm and mesogloea, and the interactions of these layers, in the sea anemone Calliactis parasitica (Couch) have been studied by examining the healing of simple wounds. Studies included the part played by the mesogloeal cells, the origin and functions of which have been much debated.

The results of morphometric and developmental studies made to elucidate the relationship between Parathemisto gaudichaudi (Guerin) and P. gracilipes (Norman) show them to be one and the same species. Apparent differences are due to differences in the size of specimens at maturity, and to the degree of development of the bispinosa-compressa condition. P. gaudichaudi takes precedence over P. gracilipes.

The species is highly variable, existing in two extreme forms, the bispinosa form and the compressa form, together with all possible intermediates. The full range of the bispinosa-compressa condition is not expressed until a body-length of 10 mm is reached. Specimens are capable of changing towards either extreme at moults, but the factors causing the change are unknown.

A key to the genus Parathemisto Boeck is included.

In this investigation of the wounds occurring on blue sharks, tooth cuts were found only on females over 180 cm long, supporting the view that they are courtship scars incurred during breeding. However, it seems unlikely that these sharks normally mate in British waters. It is suggested that tooth cuts can provide information on the size at sexual maturity of the blue shark in European seas.

The colour patterns of the corkwing wrasse Crenilabrus melops and the functional significance of these patterns has been described. The resting colours of the fish are described for juveniles, mature males and mature females. These colour patterns assist in making the fish less conspicuous in their natural environment. Agonist behaviour is characterized by the development of a series of vertical bars on the body together with ritualized lateral and frontal displays in aggressive, and a head-up submissive posture in fright situations. Most aggressive behaviour is associated with the territorial activity of the mature male. Courtship and spawning activities involve a complex series of visual signals that synchronize the roles played by the male and female. The differences in colouration between juvenile and mature fish and the changes any individual can display have wrongly lead earlier authors to split C. melops into different species or varieties.

A second species of angler-fish, Lophius budegassa Spinola, 1807, is reported from British waters. This species has hitherto been reported only as far north as the Bay of Biscay. This is not thought to be an active extension of the range of this fish but to be due rather to failure to identify it, for specimens (misidentified as L. piscatorius) dating from the last century have been found in the British Museum (Natural History) collection.

The distinctive characters of both species are given.

Data collected over a period of 15 years for lobsters maintained at 10 °C and weighingfrom < 1·0 to 1200 g have been analysed. Equations have been produced defining the relationships of the cast shell weight, the growth increment at the moult, the inter-moult period and the food intake per moult with the weight of the lobster, and of the growth increment with the food intake. In particular, a growth curve has been derived showing the weight of lobsters, kept at 10 °C, with age. It is suggested that when there is an adequate food supply, the growth increment is a constant proportion of the lobster weight, and that variations in growth rate are achieved by changes in the length of the inter-moult period which, in turn, is mainly dependent upon the temperature of the environment.

A large number of nanoplankton species originally found in the sea around Britain have now been collected from other northern temperate waters (see Leadbeater, 1972 c; Manton & Leadbeater, 1974). It was, therefore, of considerable interest to collect nano-plankton from warmer waters such as those of the Adriatic and Mediterranean. The larger plankton of both the Adriatic and Mediterranean has been the subject of investigation by a succession of scientists from many countries (for references see Tregouboff, 1952). Whilst many workers acknowledged the importance of the smaller plankton from these areas (e.g. Bernard, 1958; Lalami-Taleb, 1971) only a few have attempted to study and identify species belonging to this group. In this respect the meticulous work of Lohmann (1902a, 1911) and Schiller (19136, 19256) requires special mention. Lohmann (1902a), working on the phytoplankton from the coast of Sicily, first used the technique of pumping sea water through filter paper and in this way he was able to collect and identify many minute species for which he later suggested the name ‘ Nannoplankton’ (Lohmann, 1911). On a later excursion to the Atlantic Ocean, Lohmann (1911) found the gentle centrifugation of sea-water samples was a more satisfactory and less destructive way of concentrating small cells. Schiller's most important contribution concerns a phytoplankton study carried out as part of an international hydrobiological survey of the Adriatic Sea during the years 1911–14. Schiller's findings confirmed many of Lohmann's previous observations and added a further range of new species including many green flagellates (Schiller, 1913 6, 1925b).