The copepod Asellopsis intermedia (T. Scott) is a conspicuous member of the meiobenthos in sand on a small exposed beach at Firemore, in Loch Ewe, Scotland, and is the only species of this genus so far recorded interridally from the area. Length of adults does not exceed 0.65 mm in females and 0.55 mm in males. Although it lives below the sand surface, it is not an interstitial form since it burrows by displacing the sand grains rather than by moving freely in the interstitial spaces.

Diets of the four main flatfish species, Arnoglossus laterna,Bothus podas (Bothidae), Buglossidium luteum and Solea solea (Soleidae), inhabiting shallow sandy bottoms near the Gulf of Fos (north-west Mediterranean) were analysed to elucidate food partitioning between their juveniles (1+ group) in nursery areas. The two Soleidae were principally active during the night, and the two Bothidae during the day. The four species all mainly fed on the three most abundant categories of prey in the area (polychaetes, molluscs and crustaceans) but showed different food preferences. Arnoglossus laterna and B. luteum mainly preyed on crustaceans and molluscs (gastropods and bivalves) whereas Bothus podas and S. solea preyed principally on polychaetes and bivalve molluscs. Food niche width was clearly higher in A. laterna and Buglossidiumluteum (13·3 and 14·2 respectively) than in Bothus podas and S. solea (3·2 and 3·6 respectively). Overall food niche overlaps (T) obtained for each pair of fish ranged from 0·33 to 0·58. Overlap was higher between species of the same family but did not reach a significant level. Food niche overlap differed according to the period of the day but did not show any important seasonal variation. Differences in feeding rhythms, food preferences and body sizes, reduced the direct food competition between the juveniles of the four flatfish species, allowing their coexistence within the same nursery zone, despite close periods of settlement.

Deep-water corals are known to provide essential habitat for fish and invertebrates along the continental slope in different areas of the world, offering prey to coral predators, protection or attachment substrate to other suspension feeders. In the Mediterranean Sea the coral Isidella elongata (Esper, 1788) characterizes a facies of bathyal compact mud substrates between 500 and 1200 m depth. Based on 4 experimental surveys carried out between 1985 and 2008, we obtained quantitative data on the fauna associated with live coral stands. We show that species richness of invertebrates and crustaceans, as well as abundance and biomass of crustaceans, is higher in areas with large stands of the coral. Some commercial fishery species are also more abundant or reach larger sizes in areas with high density of the coral, particularly the red shrimps Aristeus antennatus (Risso, 1816) and Plesionika martia (A. Milne Edwards, 1883). Trawling over I. elongata facies causes direct impacts on the biological assemblages by removing the habitat-forming corals, decreasing invertebrate species diversity and negatively affecting fisheries production in the long term.

The distribution of 38 nests of loggerhead turtles (Caretta caretta) on beaches on Sanibel and Captiva islands, south-western Florida (26°26'N 82°16'W), and of 70 first digging attempts by green turtles (Chelonia mydas) on Ascension Island (7°57'S 14°22'W), was quantified. For loggerhead turtles on Sanibel and Captiva, nests were clumped close to the border between the open sand and the supra-littoral vegetation that backed the beaches. This spatial pattern of nests was closely reproduced by assuming simply that turtles crawled a random distance above the most recent high water line prior to digging. In contrast, green turtles on Ascension Island clumped their first digging attempts on the uneven beach above the springs high water line, crawling up to 80 m to reach this beach zone.

The impact of colonization by Sargassum muticum (Phaeophyta: Fucales) on the resident macroalgal assemblage in tidepools was investigated in northern Spain. Sargassum muticum was allowed to colonize and spread in some tidepools, and was periodically removed in others. Changes in the abundance of macrophytes were recorded at three sites over two years. The colonization by S. muticum and the subsequent changes induced on the native assemblage was extremely variable among sites. Where the invader colonized profusely, it induced changes in the macroalgal composition of tidepools. The leathery group of macrophytes was significantly affected and changes were also observed in the foliose group. It was suggested that S. muticum may take advantage of their perennial and opportunistic traits in the interaction with groups of algae with different survival strategies. However, the spatial patchiness of the colonization may mitigate the impact of the invasion at local and regional scales.

Zinc (Zn II) and iron (Fe III) were demonstrated histochemically in cytoplasmic inclusions shown to be lysosomes in a number of cell types in Mytilus edulis. The cellular distribution of the metals differed between the sexes; males were shown to have more zinc (Zn II) in the kidney than females, the latter appearing to use oocytes as an additional means of excretion. Differences in cellular distribution of the metals was also demonstrated between the two populations studied probably reflecting availability of the metals in their respective environment.

The shell growth of small coastal Mytilus edulis L. was measured at three different constant low salinities over short periods of time. Growth was significantly depressed in 6·4 and 16‰ S but not in 22·4‰ S. Fluctuating salinities between 0 and 32‰ S depressed growth whether the fluctuations were of sinusoidal or abrupt form. After 1 week of preconditioning to constant 32‰ S the growth of coastal (Bangor) mussels was better than estuarine (Conwy) mussels. However, after two weeks’ preconditioning to 32‰ S the estuarine mussels displayed the best growth. In the fluctuating regime, both coastal and estuarine mussels exhibited poor growth rates. The long-term response of the shell growth of coastal M. edulis was followed over a period of 44 days. Salinities in the range 1·8–9·6‰ S were lethal to the mussels within 10 days. In 12·8 and 16‰ S growth was initially delayed but recovered eventually. There was a gradual decline in the growth rate of the mussels exposed to the higher salinities (19·2–32‰) and an improvement in the growth of the mussels living in lower salinities (12·8 and 16‰) to levels nearly matching that of the high salinity animals by day 37. This suggests that acclimation of the shell growth of M. edulis to salinities in the 12·8–28·8‰ S range was achieved by the mussels during the experimental period.

The developments of Polydora ciliata Johns, and Polydora hoplura Clap, are described from the egg to a very late planktonic stage in the case of the former, and to young metamorphosed individuals in the case of the latter. Only external characters are described.

In both species the eggs are laid in egg-sacs attached to the wall of the parent's burrow.

The larvae of P. ciliata are released at a stage with three chsetigerous segments and lead a long planktonic life.

The larvae of P. hoplura are provided with special food in the form of yolk-masses ; they undergo most of their development while in the protecting burrow of their parent; are released at a very late stage, and have only a short planktonic life.

The larvae of both species have a complicated vestibule surrounding the mouth, and are provided with special sensory cilia on the head.

The larvae are provided with a special kind of cilia, situated at the ends of every nototroch, which are used to take hold of the long provisional bristles in swimming. This suggests that one of the functions of the long bristles is that, in conjunction with these grasping-cilia, they increase the rigidity of the swimming larva, and hence the efficiency of its driving cilia.

Previous references to Polydora larvae are briefly discussed.

The development of the oocytes of Nereis (Hediste) diversicolor and Nereis (Nereis) pelagica takes up to 18 months from their first appearance in the coelom to maturity, and in the natural conditions experienced by the population studied in north-east England the females are in their second year before the oocytes begin to appear. The duration of spermatogenesis is less than that of oogenesis, taking up to 6 months for completion. This information permits a more rigorous interpretation of the size frequency data which have been obtained from a biometrical study of the jaws. In the populations of both species the majority of individuals seem to reach maturity when 3 years old.

The length, breadth, and in part the height, of individual Balanus balanoides and B. crenatus have been measured over several seasons, and the mean specific growth-rates calculated. The B. balanoides had settled at various known intertidal levels, and both species under conditions of permanent submersion.

Under all conditions, except on the highest intertidal panels, length increases rapidly subsequent to settlement and during the early summer. B. crenatus can reach its virtual maximum size (20–25 nun. rostro-carinal length) in a single growing season, under the conditions studied. Late-settled B. crenatus continue to grow further into the autumn, and begin to grow again early in the spring of the second season at the end of which the virtual maximum size is reached. The seasonal growth of both intertidal and submerged B. balanoides is similar, but the growth-rate is a function of submersion, which is, of course, dependent upon the tidal level. However, maximum growth is not reached in the first season and there is consequently relatively more growth in the second season than in B. crenatus.

The mean specific growth-rates in both species decrease with increasing size and, with permanently submerged B. crenatus, there is no suggestion that during the first spring and early summer any change in the environmental factors was effective. On the intertidal panels, the mean specific growth-rates at a given size vary with the tidal level, and this effect is most marked in the smaller barnacles.

The impact of shrimp fisheries in tropical regions has become comparable to the world's most intensively exploited temperate shelf ecosystems. The increase in the fishing fleet in south-eastern Brazil and the decrease in landings of profitable shrimp species have contributed to the incorporation of additional species into those fisheries. The goal of the present study is to investigate the influence of environmental factors on the abundance patterns of shrimp communities on the south-eastern coast of Brazil, over a period of two years. Monthly collections were conducted in the Ubatuba and Caraguatatuba regions using a commercial shrimp fishing boat equipped with ‘double-rig’ nets. Each region was divided into 7 sampling stations up to 35 m deep. The relationship between the environmental factors and the abundance patterns in the shrimp communities was assessed using a canonical correlation analysis (CCorrA). The first set of variables used during the CCorrA included environmental characteristics and the second set of variables the abundance of the studied species. A total of 374,915 individuals were collected during the present study. Xiphopenaeus kroyeri showed the highest abundance (273,127), followed by Artemesia longinaris (73,422), and Pleoticus muelleri (15,262). In the first root, depth and temperature showed the highest factor loadings (0.9 and −0.7) and canonical weights (0.6 and −0.4). These environmental factors were strongly associated with the abundance of X. kroyeri (factor loading =−0.9 and canonical weight =−0.9). The second root demonstrated a positive relationship between abundance of P. muelleri and depth, and an inverse association with bottom temperature. The abundance patterns of X. kroyeri and P. muelleri were strongly affected by the water mass South Atlantic Central Water (cold waters =15°C), which can lead to a temperature decrease in deeper areas (>15 m). Thus, the opposite abundance trend for depth of these species might reflect bathymetric variation in temperature, a clear example of distinct behavioural differences of species of different origins, either tropical (X. kroyeri) or subantarctic (P. muelleri). The low overall association between environmental parameters and shrimp abundance patterns indicates that each studied species might have responded idiosyncratically to environmental variation, such that a general community-level response was not apparent. However, other confounding factors such as intraspecific migration patterns might have also played a role in generating the observed patterns.

The orientations of the reflecting layers in the external surfaces of the herring have been found both by light-measurements on the fresh fish and by histological studies on preserved specimens.

The reflecting platelets which lie under the scales are orientated, with respect to the surface of the fish, in a similar way to the platelets found in the bleak and described earlier by Demon & Nicol (1965). However, on the curved dorsum of the fish, although the reflecting platelets are much more perpendicular to the sea surface than the scales on which they lie, these platelets are still inclined some 20° to the perpendicular. It is shown that, in this region, the fish reflects the fraction of the light striking the platelets which is sufficient to match the background against which the fish is seen. The platelets on the curved dorsum have the property of reflecting green light well if it falls obliquely on them but reflecting it poorly when it strikes them at angles close to normal incidence. On the broad flank of the herring the scales have reflecting platelets under most of their surfaces, and the individual scale has several distinctly coloured regions. When we look at any particular region of the flank of an intact fish we are always looking at several overlapping layers differing greatly from one another in their spectral reflecting properties.

It is the combination of the reflexions of several layers which gives the very bright silvery reflexions of the intact fish. A system of overlapping scales of this kind is needed even to reflect one waveband of light well over a wide range of angles of incidence.

The calcareous sponge Paraleucilla magna has been detected at different Mediterranean sites (Taranto, Porto Cesareo, Brindisi and Naples). Its record in well studied areas where several benthic surveys have previously been carried out suggests a recent introduction of the species into the Mediterranean Sea. Until now this sponge has only been recorded from the Brazilian coast. It shows different morphologies, varying from tubular to an irregular massive shape with several folds occurring on its surface. The colour is white-cream. The surface is smooth. The consistency is friable. The oscula are 10–20 mm in diameter and located at the top of tubular protrusions. The skeleton consists of cortical and subatrial triactines and tetractines, together with atrial triactines, differently distributed in the sponge body. Paraleucilla magna is abundant in eutrophic environments, where seasonally it may reach very high frequency values and large dimensions. It is resistant to pollution, but it is also able to live in clean waters. The inclusion of this species among Mediterranean alien invasive species is suggested.

The family Raiidæ belongs to the division Batoidei of the sub-order Hypotremata, and is represented by the principal genera Raia, Psammobatis, and Sympterygia (Regan, 1906). The genus Raia (an altered spelling of Raja) was instituted by Linnæus, after Artedi, for the type Raja batis in the Systema Naturæ, Ed. X, Vol. I, 1758. The species are numerous and mostly of northern distribution.

Increasing interest in the comparative biochemistry of marine algae and protozoa is creating a demand for experimental material in the form of pure, i.e. bacteria-free, cultures. For nutritional and biochemical studies pure cultures are, of course, obligatory; but the number of marine strains available for this sort of work is lamentably small. Indeed, none of the so-called μ flagellates has hitherto been grown in pure culture as far as I know, although there exist pure strains of some of the larger and hardier forms.

Laboratory observations indicate that larvae of Pecten maximus (L.) pass through three phases of swimming behaviour before metamorphosis. Trochophores and early veligers generally swim upwards and, in shallow containers, tend to accumulate at the surface. Their swimming cilia beat without interruption so swimming is continuous. After 3 days of development, pauses in ciliary beating occur intermittently and the veliger becomes capable of withdrawing into its shell. It alternately swims up a vertically orientated spiral and sinks. This type of swimming behaviour is also displayed by the pediveliger, but this larva also periodically swims close to, or crawls on, the substratum. The tendency to accumulate at the surface becomes less pronounced as larvae grow older. By the pediveliger stage it is replaced by an increasing tendency to accumulate close to the substratum.

Recent molecular detection of vast microbial communities exclusively associated with sponges has made evident the need for a better understanding of the mechanisms by which these symbiotic microbes are handled and transferred from one sponge generation to another. This transmission electron microscopy (TEM) study investigated the occurrence of symbiotic bacteria in free-swimming larvae of two viviparous species (Haliclona caerulea and Corticium candelabrum) and spawned gametes of two oviparous species (Chondrilla nucula and Petrosia ficiformis). Complex microbial communities were found in these sponges, which in two cases included bacteria characterized by an intra-cytoplasmic membrane (ICM). When ICM-bearing and ICM-lacking bacteria co-existed, they were transferred following identical pathways. Nevertheless, the mechanism for microbial transference varied substantially between species. In C. nucula, a combination of intercellular symbiotic ICM-bearing and ICM-lacking bacteria, along with cyanobacteria and yeasts, were collected from the mesohyl by amoeboid nurse cells, then transported and transferred to the oocytes. In the case of Corticium candelabrum, intercellular bacteria did not enter the gametes, but spread into the division furrows of early embryos and proliferated in the central cavity of the free-swimming larva. Surprisingly, symbiotic bacteria were not vertically transmitted by P. ficiformis gametes or embryos, but apparently acquired from the environment by the juveniles of each new generation. This study failed to unravel the mechanism by which the intercellular endosymbiotic bacterium found in the central mesohyl of the H. caerulea larva got there. Nevertheless, the ultrastructure of this bacterial rod, which was characterized by a star-shaped cross section with nine radial protrusions, an ICM-bound riboplasm, and a putative membrane-bound acidocalcisome, suggested that it may represent a novel organization grade within the prokaryotes. It combines traits occurring in members of Poribacteria, Planctomycetes and Verrucomicrobia, emerging as one of the most complex prokaryotic architectures known to date.

The distinguishing features of the common squid of British waters, Loligo forbesi, are summarized, and contrasted with those of L. vulgaris. The life-cycle and growth of L. forbesi are described, based on samples from trawl catches off Plymouth. This species seems to be an annual - young squid first appear in the trawl in late May, when their length is about 10 or 11 cm. Subsequent growth is rapid, and the males reach 30 cm and the females 25 cm by November. Spawning takes place mainly in December-January, but may continue into the spring. Neither sex survives beyond a single spawning season. Hatching of the spawn probably takes 30–40 days, and if the young squid taken in the trawl in late May hatched in the early part of the same year, a growth rate of about 25 mm/month would be required. Known growth rates for other species of Loligo are about 20 mm/month, so that indicated for L. forbesi does not seem to be impossibly high. The life-cycle is summarized in Fig. 8. There is also a summer spawning population, which grows to a rather smaller size at maturity, and which also seems to be annual.

During the summer L. forbesi ranges throughout the English Channel and southern North Sea, particularly in inshore areas. In October the squid migrate farther offshore and tend to occupy the western part of the Channel.

Values for total weight of squid/2 h trawl are given, on a monthly basis, for 1966–9. The largest quantities are usually taken in October and November, the highest single figure being 30.54 kg/2 h trawl, in November 1967.

Nitrogen retained and nitrogen excreted by Calanus finmarchicus (Gunnerus) have been measured at all stages of development from egg to adult; and the percentage of food digested by adult females grazing algal diets has been estimated by two separate methods. The data have been used to calculate gross efficiency of growth by the young stages as well as that of egg-production by the adult female. They show that during a life-span of approximately ten weeks the animal uses 24% of the nitrogen it captures as food in order to build new tissue and produce eggs; the remaining larger fraction is lost as faecal pellets, moults and excreted end-products of metabolism.

Basket-stars are suspension-feeders and suspension-feeding by other brittle-stars was suspected long ago on circumstantial grounds, but it is only in the last twenty years that it has been actually demonstrated, and detailed descriptions of suspension-feeding behaviour are still available for only a handful of species. Blegvad (1914) pointed out that Ophiothrix fragilis (Abildgaard) and other species lead sedentary lives and feed largely on detritus on, or near, the sea-floor. Wintzell (1918) explicitly suggested tha and Ophiopholis aculeata (L.) are suspension-feeders, primarily on the grounds that they are commonly found in current-swept localities where plankton is rich, in association with known suspension-feeders such as Modiolus, Lima and Alcyonium. The same suggestion was made by Vevers (1952) who noted the occurrence of dense aggregations of O. fragilis in offshore, current-washed areas near Plymouth, and who later observed suspension-feeding behaviour in that species and in Ophiocomina nigra (Abildgaard) (Vevers, 1956). This was only the second time that suspension-feeding had been documented for any (ophiurid) brittle-star, but now it has been described in about a dozen species and suspected in others, mostly members of the Amphiuridae, Ophiactidae, Ophiothricidae and Ophiocomidae (MacGinitie, 1949; Kuznetsov & Sokolova, 1961; Moore, 1962; Magnus, 1964; Buchanan, 1964; Fontaine, 1965; Fricke, 1970; Pentreath, 1970).