Since the advent of nuclear fission, considerable interest has been aroused in the biological fate of strontium, as two isotopes of this element are among the longer-lived fission products of uranium. Strontium 90, in particular, constitutes the major hazard in old fission products because it is readily taken up by all kinds of plants and may then be concentrated in the bones of animals feeding on the plants. Strontium 90 contamination may be derived from fall-out from atomic explosions or from uncontrolled disposal of fission products. The oceans should receive more than twice as much Strontium 90 from fall-out as the continents because 70% of the surface area of the globe is covered by sea. The oceans are also used, though to a very limited extent at present, for the disposal of fission products from reactor wastes. Hence it is obviously important to study the behaviour of strontium in marine organisms in order to evaluate the health hazard caused by controlled or uncontrolled radioactive contamination of sea water. Barium has only relatively short-lived fission-product isotopes, but can readily be studied at the same time as strontium because of its similar chemistry.

An account is given of some features of the organization of the endostyle of Amphioxus, with particular reference to the distribution of sites of mucus secretion as indicated by positive responses to tests for acid mucopolysaccharides. Autoradiography shows that the centre of distribution of organically-bound iodine is associated with the tips of the mucus-secreting cells of zone 5, and not with the glandular tracts. Mucus secretion also occurs elsewhere in the endostyle (although not in the dorsal glandular tracts), but as it is not associated with any accumulation of bound iodine it is concluded that the binding in zone 5 is a specialized property of the cells of that particular zone. The results are discussed in the light of recent work on the protochordates and the ammocoete larva, and it is concluded that in Amphioxus, as in the Tunicata, there is reason for supposing that the iodination process is a biochemical specialization and that its product must therefore be of some physiological significance to the organism. Attention is also drawn to the evolutionary interest of the association of iodine-binding with a mucin rather than with a glycoprotein.

In the course of a study by Gibbs (1984) of the reproductive biology and the population dynamics of the bivalve Abra tenuis (Montagu) collected from the Fleet, a brackish water lagoon in Dorset, and from the Plym Estuary, Plymouth, a number of species of apparently pathogenic larval digeneans was found. These could not be satisfactorily identified from their larval characters alone, and following collaboration with Professor J. Llewellyn (personal communication) it was decided that they should be made the subject of a further study.

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.

The family Myidae is represented in British seas by the two large and well-known species, Mya arenaria L. and M. truncata L., which burrow deeply into muddy sand and into stiff mud or clay respectively, and by the much smaller Sphenia binghami Turton. Interest in members of this family of Eulamellibranchia was aroused during 1949 when studying two species which are common along the coast of California, namely Platyodon cancellatus (Conrad) and Cryptomya californica (Conrad). These differ most interestingly in habitat. The former bores into soft rocks between tide marks, and the latter, although practically devoid of siphons, burrows deep in the mud of tidal estuaries, always in association with burrows made by various large invertebrates. The species most usually involved is Callianassa californiensis, a large anomuran prawn (McGinitie, 1935). The almost sessile siphons open into the sides of the burrows. Accounts of both species have been prepared for publication in California.

Between May 1961 and November 1970 almost monthly visits were made to Duckpool, an exposed shore on the north coast of Cornwall, where Sabellaria alveolata (L.) is the dominant organism on low-level rocks uncovered only by spring tides. Massive colonies several feet across and up to some 2 ft thick, formed mainly of shell particles cemented together by the worms, as well as many smaller colonies and single tubes, here reach their maximum development in south-west England.

Selected sites and colonies were photographed and some measured at frequent intervals over long periods of time. comparative studies of long series of colour transparencies examined closely with a binocular microscope have proved invaluable in elucidating the manner and rate of growth of varied types of colonies, their lengths of life and the manner of their ultimate destruction. Detailed histories of these selected colonies are given in this paper and reveal much that was previously unknown or only guessed.

A short spawning period every year in July initiates each new generation. Experimental work, already published, had shown that individuals develop at different rates, the final stage with ability to settle being reached at any time from 6 weeks to 6 or more months, and when reached the ability can be retained for some weeks. This accords with observations on the shore, where settlement takes place in any month between late August and the following early May, or rarely June. The intensity of settlement varies enormously from year to year, there being none in some years, with slight or moderate or heavy settlements in others.

At an early stage of an autecological study of Gracilaria verrucosa (Hudson) Papenfuss it seemed possible that the best growth of the plants occurred in places, such as the Achill Sound and the Church Island Channel in the Menai Straits, where, in the absence of heavy wave action, strong currents flowed over the plants. Experiments were carried out, in the sea, to investigate the effect of currents on the growth rate; the apparatus used and described here would probably be suitable for the investigation of current effects on other sedentary marine organisms.

These experiments also led to some observations on the effects of illumination on the pigmentation and growth rate of the plants which were supplemented by laboratory experiments. High intensity illumination in the laboratory also demonstrated positive phototropism in the plant.

The greater number of the species given in this list are new records for the Plymouth region. Recent records for some rare species have also been included.

Twenty-six species of marine planktonic algae, belonging to 8 taxonomic divisions, were tested tinder axenic-culture conditions for their capacity to grow, under cool-white light, on nitrate, nitrite, ammonium, urea, glycine, D-glucosamine or hypoxanthine as sole nitrogen source. The culture medium was composed of Mediterranean oligotrophic sea water enriched with phosphate, silicate, trace-metal ions and vitamins, and buffered at pH 7.5–80. Each nitrogen compound was tested at a fixed concentration of 500 μg-at. N per litre.

The pigments in the crowns of a number of sabellids and serpulids have been examined. The main pigments of sabellid crowns are ommochromes, but these pigments have not been found in serpulids. Both sabellids and serpulids also possess astaxanthin, and in Serpula, Protula and the sabellid Chone infundibuliformis it is to this pigment or an ester that the colour of the crown is due. The main carotenoids have been identified and the presence of a possible intermediate ketocarotenoid in amounts varying from one species to another suggests that the astaxanthin or astaxanthin ester is synthesized by the worms from carotene derived from the food. Pomatoceros has pink and blue pigments, and Galeolaria a similar grey-blue pigment which could not be identified with any known class of pigment. Neither these nor ommochromes have previously been found in annelids.

Measurements of current at the Seven Stones Light Vessel, 50° 03·5' N. lat., 6° 05·1' W. long. (for position, see Cooper, 1960b, fig. 1) were first made with the Carruthers Drift Indicator between 17 August and 15 September 1933 (Carruthers, 1934). The much longer series with the Vertical Log between July 1939 and April 1941 showed average travel of the residual cur-rent at a rate of 2·5 miles per day towards east-south-east (110° true) (Carruthers, Lawford & Veley, 1951). It was shown clearly that there was a strong causal connexion between the direction and strength of the wind and direction and strength of current, but that there were evidently other factors concerned as well. These current measurements were not easy to reconcile with deductions from the observed distributions of temperature and salinity in the area (Matthews, 1914; Harvey, 1925, 1929; Cooper, 19606). A rational explanation could be achieved if it is assumed that the passage of water from the English Channel to the Bristol Channel occurs intermittently and is confined to a narrow current close into Lands End. This ‘corner current’ rarely extends as far west as the Seven Stones Light Vessel.

Post-traumatic regeneration of arms in Cephalopods is a common occurrence. It was described by Aristotle and, in more modern times, by Steenstrup (1856). Féral (1978) summarizes the information on regeneration of arms, tentacles and suckers in cephalopods. He reports only one case, experimental, involving a Sepiolidae species, namely Sepiola atlantica.

This paper gives an account of regeneration of the copulatory arm in three wild-caught male sepiolid squids, two of which were Sepietta oweniana (d'Orbigny, 1841) and one Sepiola ligulata Naef, 1912 (Sepiolidae: Sepiolinae). The copulatory arm, or hectocotylus, is the left dorsal arm in Sepiolinae. It represents a most important means of species identification (Naef, 1923; Bello, in press). The squids were caught by bottom trawl in the southern Adriatic Sea during routine sampling. Measurements and observations were made on preserved specimens.

Monthly samples retrieved from the previously unstudied Plym Estuary, from January 1994 to November 1994, were analysed for living and dead Foraminifera. An assemblage composed of three hyaline species; Haynesina germanica, Elphidium williamsoni and Ammonia beccarii var. batavus, was identified. Further samples were taken to assess depth distribution, microdistribution and lateral distribution, to compliment the original sample suite. A comparison of the dead assemblage to the live assemblage revealed similar species proportions in both assemblages, reduced test abundance in the dead assemblage, and the presence of rare estuarine and marine species in the dead assemblage. This study has revealed a complex interplay of species resulting in several foraminiferal blooms throughout the year; the largest occurring in May.

The work described in this paper is a contribution to the general problems of rearing the larvae, and growing the spat of the European flat oyster, Ostrea edulis L.

The specific aspect of the problem dealt with in detail is the place taken by minute motile organisms (naked dinoflagellates and other unicellular algae) in the food requirements of the developing veliger larvae.

Six such flagellate organisms, ranging in size from 1·5 to 7 μ in diameter, have been isolated from sea water, and are maintained in pure culture, under conditions described. Pending specific identification, these are denoted by letter-labels only. These organisms have been used, over a period of years, in feeding experiments with oyster larvae.