The release of larvae by female lobsters is confined to a few minutes at night, and is repeated at a similar time on each night over several weeks. The rhythm is shown to be partly controlled by an endogenous component in the female. Eggs in vitro have an exogenous, light-stimulated hatching rhythm, but are arhythmic in continuous light or darkness. In light/darkregimes the time of hatching is not influenced by daylength, but occurs sooner after sunset astemperature increases.

The pronounced Bohr shift of cephalopod haemocyanin may be related to the formation of octopine, rather than lactate, by cephalopod muscle. Octopine is a much weaker acid than lactate.A highly pH-sensitive oxygen binding curve would permit the efficient unloading of oxygen at the tissues even for a moderately small decrease in venous pH.

Phytoplankton from Loch Creran, Argyll was maintained in continuous culture for 41 days. During most of this time the mixture of species retained the diversity and dominance pattern typical of summer phytoplankton in the loch, notwithstanding the manipulation of algal nutrient status to bring about phosphorus control of growth. Results suggest that most detritus was washed out early in the experiment.

The aim of the experiment was to test the applicability to natural multispecies phytoplankton of part of Droop's (1974, 1975) model of nutrient-limited algal growth. ‘Quasi-steady states’ with respect to concentration of chlorophyll, particulate carbon (PC), particulate phosphorus (PP) and particulate nitrogen (PN), wereobserved at two levels of input of dissolved inorganic phosphorus. At other times the algal phosphorus quota (estimated from the ratio of PP to PC) varied from about 0·002 to 0·015 atoms P per atom C. Specific growth rate was estimated from the rate of increase of PC. During part of the experiment, growth rate was linearly related to reciprocal phosphorus quota, thus confirming the applicability of the model.

The fact that Spirorbis spirorbis (= S. borealis) has a summer breeding season during which several successive broods of larvae are produced has been known since the work of Garbarini (1933,1936). A recent summary of the taxonomy, ecology and distribution of S. spirorbis has been given by Knight-Jones & Knight-Jones (1977). The two aspects of the species' reproductive biology which have received most attention are the role of sea temperatures in initiating breeding and the correlation of brood production with lunar and tidal cycles. In the present work a study has been made of gametogenesis as well as of the more easily observed cycle of brood production. The results obtained have indicated, in respect of one population of S. spirorbis at least, the need for a major re-assessment of earlier studies of the species.

So few data are available concerning polychaete fecundity that recent speculation about the relative advantages of different life-history ‘strategies’, and about the relative value of protected and unprotected larval development, has been almost completely abstract. The dangers of this approach have been clearly indicated by Stearns (1976) in his recent review. Until quantitative studies are made of the number and weight of gametes produced in relation to the weight of individuals for a range of species, there seems little basis for discussion of the problems mentioned above.

Over a period of 10 years, 1964–74, primary production has been measured at three stations across the western English Channel using the 14C method. Results for carbon fixation, cell counts and mean seasonal production are illustrated. Statistical analyses show that, at two of the three stations, carbon fixation in 1966 was significantly greater than expected and that annual production differs significantly at each of the stations. The variations observed are discussed in relation to other changes recorded in the area during the same period. A deck incubator used for simulated in situ14C experiments is illustrated.

In many marine invertebrates the presence of an active transport system for the epithelial absorption of amino acids has been conclusively demonstrated (Stephens, 1968. 1972; West, de Burgh & Jeal, 1977). It has been observed by several authors that inhibition of uptake of a given amino acid can occur in the presence of other amino acids, in a manner analogous to that observed in vertebrate gut absorption systems. Some examples are the work of Chapman & Taylor (1969) on whole Nereis virens, Ferguson (1968) on the digestive glands of Echinaster spinulosus, Ferguson (1971) on whole asteroids, Bamford & Stewart (1973 a, b) on Arenicola marina gut, and Bamford & McCrea (1975) on the gill of Cerastoderma edule.

The publication in 1953 of the English language translation of Vinogradov＇s massive compilation of data upon the chemical composition of numerous animals was a valuable landmark in this field of study. Since then, papers too numerous to summarize, have appeared in the literature employing ever more accurate analytical techniques. So far as marine animals in particular are concerned, the theme which has been consolidated by such subsequent work revolves around their ability to extract and concentrate a variety of chemical elements from their environment. Frequently, however, no obvious function can be ascribed to the more obscure of these often highly concentrated elements.

The interest in the temporal variability of the Northumberland benthos derives from a continuing time-series of samplings initiated in January 1971. Intensive sampling was started at a single station for the purpose of computing the secondary production for the years 1971–72 (Buchanan & Warwick, 1974). It became clear in the course of this exercise that there was a considerable degree of variation in species numbers and ranking, both between the two years and, seasonally, within single years. Sampling at this station was continued for a further two years - 1973–74 – and the data were interpreted as an un-broken rising trend in numbers of individuals with changes in species ranking and diversity (Buchanan, Kingston & Sheader, 1974). Since the magnitude of change over the four years was unexpectedly high, and largely unexplained, it was decided to continue the observations for an indefinite period and to expand the programme of sampling to cover several stations over a wider area of different sediment types.

An examination of infra-red satellite images of the North-West European continental shelf suggests that cross-frontal mixing takes the form of cyclonic eddies. These are about 20–40 kmin scale and persist for a few days. It is suggested that the dynamics of cyclonic eddies willbe important in the development of frontal phytoplankton blooms.

The shell closure mechanism of Mytilus edulis protects the frontal ciliary mechanism against irreversible damage by low environmental salinity levels. Previous experiments had shown that the mantle fluid of mussels exposed to fluctuating salinity regimes was held at a concentration corresponding to about 60% s.w. (20·1‰S) during the period of shell valve closure (Shumway, 1977), while the oxygen tension of the mantle cavity fell rapidly after shell valve closure to 15 mmHg and thereafter remained relatively constant until the valves reopened (Bettison & Davenport, in preparation). These conditions of salinity and oxygen tension were applied to experimental preparations and their ciliary activity assessed. The salinity conditions alone depressed activity by 39·5%. The conditions of oxygen tension alone also produced a depression of 39·5% but there were signs of recovery during the period of simulated shell valve closure. When both salinity and oxygen tension conditions were applied simultaneously a more profound depression of 64·4% was produced by the interacting factors. Exposure of preparations to salinity levels corresponding to the external environment (‘no closure’ simulation) irretrievably damaged the frontal ciliary mechanism on the first exposure to low salinity.

It is well known that if a beaker of water, to which a little sand has been previously added, is stirred, then the sand moves along the bottom and accumulates in the centre. The result is the same whether the beaker is stirred clockwise or anticlockwise. It is perhaps less obvious, but equally true, that if the beaker is placed on a rotating table, then stirring clockwise and anticlockwise produces different effects. Any stirring rate in the sense of rotation may produce a concentration of sand towards the centre (better effects may be observed with less dense material – tea leaves for example). However, if the stirring is against the rate of rotation, then it is necessary to exceed the rotation rate before sand will accumulate in the centre of the beaker. In an analogous manner, ‘spinup’ of the table produces dispersion of bottom material, whereas spin-down results in a concentration of material towards the centre of the beaker.

An estimate is made of the mean value of residual flow through the Dover Strait for each month over the 24–year period from 1949 to 1972. The estimates are based on results from a modelling investigation by Prandle (1978) where it was shown that the residual flow consists of three components, (a) a tidal residual, (b), a wind-driven residual and (c) a flow due to a long-term gradient in mean sea level. The components (a) and (c) are assumed to be constant and the value of (b) is deduced using wind data recorded by Dutch Light Vessels located in the southern North Sea.

The mean flow over the whole period amounts to 155 × 103 m3 s–1 into the North Sea with a maximum value of 364 x 103 m3 s–1 and a minimum of – 15 × 103 m3 s–1 (out of the North Sea). One notable feature of the complete time series is the surprisingly small variation in the annual mean flows; perhaps this stability in the annual flow is of significance to the marine biology of the area.

The validity of the computed time series is established by reference to comparable data including a 9–year record, from cross-channel submarine cables, of the potential induced by the flow of water through the Earth's magnetic field. Additional comparisons are also made with the results of a previous study of daily-mean flows.

The sipunculanPhascolion strombi (Montagu) is well known for its habit of sheltering in empty mollusc shells. In European waters, a variety of animals are to be found associated with this sipunculan in its shelter (see Kristensen, 1970), including the pyramidellid gastropodMenestho diaphana (Jeffreys) and the erycinacean bivalveMontacuta {Tellimya) phascolionis Dautzenberg & Fischer. Neither of these two species has been recorded as living in association withP. strombi in British waters but a recent examination ofP. strombi-inhabited shells in the vicinity of Plymouth has shown both to be present in the area.

Like all pyramidellids, M. diaphana is an ectoparasite although for many years after its description by Jeffreys (1848, as Odostomia) from Exmouth, Devon, its host animal(s) remained unknown. It was first discovered associated with P. strombi by Perez (1924, 1925) at Roscoff, Brittany, and subsequently described by Dautzenberg & Fischer (1925) under the name Odontostomia (Auristomia) perezi. The possibility ofO. perezi being synonymous with the speciesdiaphana, placed in the genus Menestho by Fretter & Graham (1962), was first suggested by Thorson (Thorson, in Robertson & Orr, 1961), a view supported by Ockelmann (Ockelmann, in Ankel & Christensen, 1963) and Kristensen (1970). Recently, Rodriguez-Babio & Thiriot-Quievreux (1974) demonstrated that the protoconchs of the' free-living' individuals (M.diaphana-type) are similar to those of individuals living withP. strombi (O.perezi-xype). In shell shape, specimens associated withP. strombi at Plymouth closely resemble the holotype ofO. diaphana, now in the collections of the Smithsonian Institution (V. Fretter, personal communication). Thus & Fischer named O. perezi without reference to it would appear that Dautzenberg O. diaphana material, or perhaps were impressed sufficiently by its regular association strombi as to regard it as a distinct species. In either case, it seems to have been now established that perezi is a synonym of diophana.

Very few field studies of the population dynamics of starfish have been undertaken; such work depends upon being able to age individuals and identify age classes in the field. Information regarding growth rates in asteroids is notoriously difficult to obtain, due primarily to the absence of any method of assessing age, except where clear and obvious recruitment and regular growth provide size/age relationships. Numerous investigations of skeletal structures in asteroids by Smith (1940), Feder (1956), Hatanaka & Kosaka (1959) and Crump (1971) have failed to reveal any trace of growth lines similar to those found by Moore (1935), Jensen (1969) and Ebert (1970) in echinoids. In forcipulate asteroids, it is well established that growth depends primarily on temperature (Vevers, 1949; Hancock, 1958) and the availability of suitable food supplies (Mead, 1900; Galtsoff & Loosanoff, 1939; Smith, 1940; Vevers, 1949; Feder, 1956, 1970; Hancock, 1958). The food availability factor acts in such a way that it is impossible to tell the age of an adult starfish from its size; for example, in the spinulosan asteroid Patiriella regularts (Verrill), Crump (1969) found that specimens kept without food for 44 weeks lost 33 % of the original body weight, whilst P. regularts which had been fed on freshly killed crabs, showed a mean net increase of 629% of the original net weight over the same period.

There are numerous examples of symbiotic associations between Foraminifera and unicellular algae. Most of these Foraminifera are larger Foraminifera which occur in the shallow, oligotrophic waters of tropical seas (Table 1). Some of the symbiotic algae have been studied by light microscopy (Table 1, nos. 1–6). Dietz-Elbrächter (1971) suggested that the symbionts of Heterostegina depressa might be diatoms. She was, however, unable to prove this statement satisfactorily. Hottinger & Dreher (1974) published electron micrographs of the symbionts of H. depressa and Operculina ammonoides. From these micrographs identification of the symbionts was not possible. To date, only the symbionts of the following Foraminifera have been classified by electron microscopy:Archaias angulatus, Sorites marginalis, Globigerinoides ruber, Hastigerina pelagica and Globigerinoides sacculifer (Table 1, nos. 7,10,12,13,14).

A rocky shore exposure scale, intended primarily for use in the Fensfjord area, Western Norway, has been prepared. This scale is developed from an earlier scale devised by Ballantine for Milford Haven, Wales, making use of species abundance curves along the wave exposure gradient. Independent evidence for the validity of the scale is provided by shell shape variation in Nucella lapillus and by the height of the black lichen zone in the supralittoral fringe. The successive steps in the preparation of the scale are outlined, definitions of the exposure grades are given in tabular form for the restricted set of species analysed numerically and descriptions are provided in an extended form to provide a fuller picture for users of the scale. It is believed that the scale will prove applicable to other rocky shores around the North Sea.

The bipinnaria larva of the five-armed starfish Luidia sarsi Diiben and Koren is unusual among bipinnariae in being exceptionally large, and more especially in that at metamorphosis the larval body detaches from the juvenile starfish it has carried and nurtured, to continue a separate existence for a considerable time. In the closely related seven-armed Luidia ciliaris (Philippi) the larva is much smaller and the larval body is completely absorbed, as is usual with starfish larvae. In neither species does a brachiolaria stage precede metamorphosis. The bipinnaria of Luidia sarsi has been especially well described and illustrated, with a discussion of earlier observations, by Tattersall & Sheppard (1934). Recorded here are my observations on the metamorphosis of six bipinnariae of Luidia sarsi and one of Luidia ciliaris, and on the subsequent growth and habits of the young starfishes developed from them. Three of the former species metamorphosed in accordance with previous accounts, but three others differed in that the larval body was partially absorbed to a greater or lesser degree.

The growth of Chlamys opercularis from three sites in the Firth of Clyde has been studied. A relationship exists between the different dimensions of the shell, but, because growth is allometric, these relationships do not remain constant throughout the life of the animal. In contrast to the rectilinear relationship between the shell dimensions, the cavity volume and the weight of the shell and the weight of the soft tissues increases exponentially with increasing shell height. The growth rings on the shell of Chlamys were shown to be truly annual and are deposited primarily during the period from April to June, providing a convenient and reasonably accurate technique for assessing the age of individual animals. The size range of the height of the first ring was quite large, with a bimodal frequency distribution. The bimodality is lost in the second and subsequent years due to differential rates of growth between large and small first-year animals. The rate of growth of Chlamys from the Clyde Sea area was determined from values for the mean height of each annual ring, and has been compared to the rates shown by Chlamys from other sites around the British Isles.