Biological precipitation of barite (barium sulphate) is highly unusual (Bowen, 1966, p. 129). This mineral forms statoliths in certain ciliates (Hubert et al. 1975), but the only animals in which it is known to occur in significant quantities are xenophyophores, a group of giant deep-sea protozoans placed in a separate class within the Rhizopoda (Levine et al. 1980). The importance of these previously obscure organisms at abyssal, and bathyal depths in the oceans has lately become increasingly appreciated, mainly through the work of Tendal (1972, 1973, 1975a, b, 1980a, b; Tendal & Lewis, 1978).

Data on stomach contents of ten bottlenose dolphins (Tursiops truncatus) stranded and by-caught around Scotland (UK) between 1990 and 1999 are presented. Although the species is resident in the Moray Firth (north-east Scotland), little previous information exists on the feeding habits of the species in Scottish waters. Cod (Gadus morhua), saithe (Pollachius virens) and whiting (Merlangius merlangus) were found to be the main prey eaten although several other fish species were also found, including salmon (Salmo salar) and haddock (Melanogrammus aeglefinus), and also cephalopods.

A meter is described which measures the volume of water which has passed through a silk net which may be either towed or lowered and raised vertically.

A double release gear and throttling arrangement allows the net to be opened and, later, closed at any desired depths.

The catch of phytoplankton, from a volume of water which has been measured by the meter, may be assessed from its content of yellow-green pigments, which readily dissolve in acetone.

A rapid method of measuring the pigment content of the catch in terms of arbitrary units of plant pigment is described. The arbitrary unit is related to numbers of two species of diatoms.

The irregular distribution of phytoplankton in the sea is considered in connexion with representative sampling with this measuring net.

An important factor in the seasonal cycle of phytoplankton growth is the establishment and breakdown of the seasonal thermocline (Sverdrup, Johnson & Fleming, 1946). When surface heating is sufficient, more buoyancy is produced than can be dissipated by wind and tide. The stabilization of the water column allows the phytoplankton sufficient time in the surface layer to utilize the light energy for increased net production and the spring bloom is triggered. At the end of the summer period the erosion of the thermocline may result in an increase of nutrients in the upper layers. If production has become limited by surface depletion of nutrients during the summer, then the thermocline breakdown may result in an autumnal bloom particularly if a period of calm sunny weather follows. The importance of the thermocline development and season length is clearly illustrated in plankton studies of the North Atlantic, for example Robinson (1970).

The description of a new species of the genus Chrysochromulina, C. chiton, includes for the first time some evidence from the electron microscopy of sections in addition to the techniques previously used. Important diagnostic characters are the exceptionally large scales, which are shown to be of two kinds, the larger being saucer-shaped, and the smaller plate-like with a narrow rim flexed towards the upper surface; the structure and arrangement of the two types of scale on the body are described. Anatomical facts are given for the first time for the internal structure of the haptonema; in this species this organ consists of three concentric membranes surrounding a ring of seven fibres or tubes, the centre of the haptonema being hollow; this combination of characters distinguishes the organ fundamentally from a flagellum. Microanatomical facts are also given for the following major cell organs: the nucleus, the chromatophores including the pyrenoids, mitochondria, putative golgi material, muciferous bodies, the flagellar bases (preliminary observations only). Other distinguishable cytoplasmic components include the surface membrane, unsaturated fat bodies, vesicles of various kinds and granular protoplasm in the interstices.

Free-swimming planktonic larvae of most species of sedentary marine invertebrates do not metamorphose in mid-water and settle at random, but possess considerable powers of delaying metamorphoses until a suitable substrate is encountered. Within recent years several workers have analysed the physical properties of a substrate to which larvae respond, particularly amongst those species which are restricted in their distribution in the littoral zone to the surfaces of other animals and plants. The serpulid Spirorbis borealis occurs most abundantly on Fucus serratus; experiments conducted in which surfaces treated with extracts of F. serratus were offered as alternatives to untreated surfaces illustrated that the larvae settle on these extract-treated surfaces in significantly greater numbers. It has been demonstrated that this response is to some chemical substance derived from the alga rather than to changes in physical properties of the surface such as increased thickness of the overlying film, or changes in the surface texture. Contact with this substance modifies the settlement behaviour from that observed amongst larvae settling on untreated surfaces. The photopositive behaviour is curtailed, and the duration of the crawling behaviour preceding settlement abbreviated. The precise mechanism by which the larvae respond to the active substance is as yet unknown, but observations have illustrated that it is dependent upon the larvae detecting the active substance as an adsorbed layer on the surface rather than a response to concentration gradients in solution. The significance of an innate ability to detect specific substrates by chemical structures characteristic of the surface in the speciation of the Spirorbinae has been discussed.

We describe the diet of bottlenose dolphins Tursiops truncatus in Galician waters, north-western Spain, based on 82 non-empty stomachs recovered and analysed from stranded animals between 1990 and 2005, quantifying interannual and seasonal variation in the diet, as well as dietary variation related to sex and size. The most important prey species (in terms of numerical importance and biomass) were blue whiting (Micromesistius poutassou) and hake (Merluccius merluccius), both of high commercial importance in Galician waters. Most blue whiting eaten by dolphins were mature fish but the estimated total consumption was relatively low (around 10%) compared to Spanish fishery landings of this species. In contrast, most hake eaten by dolphins were probably immature but the estimated total consumption is more than 20% of current annual fishery landings. The diet of by-caught animals, which made up around one third of the sample, was very similar to that in the overall sample. Although bottlenose dolphins are often seen close inshore, evidence from the diet suggests that they feed at the shelf edge. Evidence was found of ontogenetic dietary shifts and differences between diets of male and female dolphins. There were also clear changes in average diet over the 16-year study period, although there was no evidence that they were in response to changes in fish abundance. The amount of hake in the diet remained stable against a background of falling local abundance while the amount of blue whiting declined despite an increase in spawning stock size.

This article presents biological data and an assessment of the conservation of the olive ridley sea turtle (Lepidochelys olivacea) population nesting in the States of Sergipe and Bahia, north-eastern Brazil, between 1991/1992 and 2002/2003. Projeto TAMAR-IBAMA (the Brazilian Sea Turtle Conservation Programme) maintains seven field stations in that region to monitor nesting activity over 339 km of beach. An increasing trend was observed in the estimated number of nests per nesting season: from 252 nests in 1991/1992 to 2606 in 2002/2003, an approximately 10-fold increase in 11 years. The available data and biological knowledge suggest that TAMAR's conservation efforts may have contributed to the significant increase in olive ridley nesting in Sergipe and Bahia; that increase is not only of regional importance, but also of significance at the western Atlantic level.

The anatomy of the teleost lymph system is considered in relation to the observed flow of lymph. The plaice Pleuronectes platessa L. was studied.

The vessels described by anatomists as longitudinal ventral, dorsal and lateral lymph ducts do not pass lymph to the head but act as collecting sinuses; the lymph flows from these sinuses to the neural lymph duct via the interspinal ducts.

At the junction of each interspinal duct and the neural lymph duct there is a simple valve. Lymph drains through this system as a result of a negative pressure developed in the neural canal by the respiratory movements of the gill apparatus.

The rigid nature of the neural lymph duct and the valves where the interspinal ducts join it allow the negative pressure to develop from a negative positive gill generated pres-sure cycle in the cephalic lymph sinuses. Valves Unking cephalic lymph sinuses aid the return of lymph to the duct of Cuvier using the same pressure cycles.

The drainage system is different in the salmonidae where the neural lymph duct is degenerate and the network of peripheral ducts serve as lymph return ducts. This can probably be explained by the occurrence of higher circulation pressures in the salmonidae.

Lymph from the neural lymph duct is a clear fluid having a composition similar to that of blood plasma. Like blood, lymph clots, and contains normal blood levels of mobile leucocytes and thrombocytes and lymph reflects blood levels of lactate. Lymph contains nearly no erythrocytes and the protein concentration of neural duct lymph is 80–4% that of blood plasma.

Published information on the diet of Cuvier's beaked whales Ziphius cavirostris (Odontoceti: Ziphiidae) is reviewed and new information on the stomach contents of three animals: two stranded in Galicia (north-west Spain) in February 1990 at A Lanzada, and in February 1995 at Portonovo; and the third stranded in February 1999 in North Uist (Scotland), is presented. The whale stranded in 1990 was a male; the other two were adult females. All animals were >5 m long.  The limited published information on the diet of this species indicates that it feeds primarily on oceanic cephalopods although some authors also found remains of oceanic fish and crustaceans.  Food remains from the three new samples consisted entirely of cephalopod beaks. The Scottish sample set is the largest recorded to date for this species. The prey identified consisted of oceanic cephalopods, mainly squid (Cephalopoda: Teuthoidea). The most frequently occurring species were the squid Teuthowenia megalops, Mastigoteuthis schmidti and Taoniuspavo (for the Galician whale stranded in 1990), Teuthowenia megalops and Histioteuthis reversa (for the second Galician whale) and T. megalops, Gonatus sp. and Taoniuspavo (for the Scottish whale). Other prey included the squid Histioteuthis bonnellii, Histioteuthis arcturi and Todarodes sagittatus as well as Vampiroteuthis infernalis (Cephalopoda: Vampyromorpha), Stauroteuthis syrtensis and Japetella diaphana (Cephalopoda: Octopoda). The squid eaten (estimated from the measurement of the lower beaks) included juvenile and mature individuals of the most important species (Teuthowenia megalops, Gonatus sp.).  The range of species found in the diet of Z. cavirostris is greater than that reported for sperm whales and bottlenosed whales in the north-east Atlantic.

During daytime low tides on the River Avon at Bristol, England, the exposed river banks become a deep green colour owing to the presence of enormous numbers of Euglena obtusa which emerge out of the black mud. Cell densities on the surface surpass 105 cells/cm2. Before the tide returns to cover the area, the cells re-burrow back into the mud and remain there during high tide and throughout the night.

The cells can be prevented from emerging on to the surface mud at low tide by artificially darkening the area with an opaque covering just as the tide recedes. Cells which are already on the surface can be made to re-burrow by similarly placing them in darkness.

The vertical-migration rhythm will persist in the laboratory in constant illumi-nation, constant temperature, and away from the influence of the tide, for nearly one month. In these conditions the rhythm is diurnal, rather than tidal. The rhythm will not persist in constant darkness.

Because of the excessive turbidity of Avon water, each high tide imposes a period of darkness on the surface mud. It is thought that these dark periods transform the fundamental diurnal rhythm into one of tidal frequency.

Various intensities of constant illumination alter the form and amplitude of the rhythm, but not the period. The stable nature of the period, under different light intensities, is thought to be due to a unique, self-stabilizing feature inherent in this type of rhythm.

The rhythm is inhibited at 2° C. Between 5° and 15° C, the period of the rhythm is virtually unaltered; it remains approximately 24 h in length.

Stomach contents of 893 blue shark (Prionace glauca) caught off Ensenada, Todos Santos Bay, Baja California, from 1995 to 1997 were analysed. 614 had identifiable food remains. A large variety of pelagic cephalopods occurred in 55.5% of all stomachs and accounted for 46.2% of all prey and 84% by estimated weight of stomach contents. The most abundant (17%) and frequent (32%) was Histioteuthis heteropsis and the most important by estimated weight (22%) was ‘Gonatus californiensis’. Argonauta spp. and Vampyroteuthis infernalis were also abundant prey. A pair of beaks of giant squid Architeuthis sp. constitutes the first record for Mexican waters. Feeding habits and the probability of scavenging on mesopelagic cephalopods is discussed. The single most abundant prey was the pelagic, red crab Pleuroncodes planipes (41.7%). Other prey included teleost fish, amniotes and floating items. Diet varied greatly between months with no clear seasonal pattern. Tiny diet differences due to shark size or sex were inconclusive. A thorough review of studies on blue sharks stomach contents analysis is given. Blue shark feed on a large variety of passive pelagic prey, mainly mesopelagic cephalopods, that could be preyed upon as well as scavenged. Depletion of this predator due to overfishing may be leading to unknown cascading top-down effects in the mesopelagic realm.

Onchidella celtica lives in communities in intertidal rock crevices, emerging only when uncovered by the tide during the milder months (March- November). It feeds on young algae and diatoms, rasping them from the rock with the radula which is lubricated by a mucous saliva. The distensible crop and stomach afford ample storage space for the food. The stomach consists of three chambers (Fig. 2), and the dorsal (d) and ventral (v) chitinous plates of the posterior one, the gizzard, crush the contents and help to direct the soluble portion towards the ducts of the digestive gland. There are three of these the two anterior (Id, rd) are large and lead from the initial chamber of the stomach (ic), the third (pd) is small and joins the posterior wall of the gizzard (pzv). The digestive gland secretes into the stomach; no cellulase occurs. Feeding experiments suggest that the digestive cells of the gland absorb only fluid. Lime and excretory cells occur in the crypts of the digestive epithelium, the latter concerned with taking up excretory matter from the blood and elaborating it into spherical masses for evacuation with the faeces

The amino acid composition of adult female Calanus helgolandicus Claus and particulate material at station L4 has been analysed from March to December. The average concentration of amino acid nitrogen in Calanus was 7·7% of the dry body weight and accounted for 83% of the total nitrogen. The average level of amino acid nitrogen in the particulate material was 11·9 μg/1. and accounted for 54% of the total nitrogen.

The relative quantities of amino acids in Calanus remained remarkably constant throughout the year. The relative quantities of amino acids in particulate material were more variable.

The rate of respiration of Calanus measured at 8°C varied from 31 μl. O2/mg. dry body weight/day in winter (December–February) to 79 μl. O2/mg dry body weight/day in summer (April–August).

Starving winter Calanus lost 1·8% and starving summer Calanus 2·1% of their dry body weight as amino acids each day. In order to replenish its daily losses of amino acids winter Calanus must sustain a filtering rate of about 30 ml./animal/day: the corresponding value in summer is greater than 50 ml./animal/day.

The amino acid composition of Skeletonema costatum is so close to that of the particulate material in the sea, that, as far as amino acids are concerned, Calanus would gain no nutritional advantage by selecting the diatom in preference to the amino acid containing fraction of particulate material as a whole.

The investigation described in the present paper was commenced in 1895, with the aid of a grant of £100 from the Government Grant Committee of the Royal Society to meet the expenses of boat-hire, and a further grant of £25 has been made by the Society to assist in the production of the charts by which the paper is illustrated. The object of the investigation has been to gain an accurate knowledge of the distribution of the fauna on the sea-bottom over a continuous area, i n order to ascertain and where possible to explain the changes which take place in the animal population when the nature of the bottom-deposit changes. At the same time it was hoped that fresh light would be thrown upon the general question of the distribution of life on the sea-bottom and the principles upon which it depends.

It has been known for a long time that the commonest British sea anemone, Actinia equina L., incubates its young in the gastric cavity (Dalyell, 1848).

The variation in species composition of continental slope fishes as determined by the catches of different trawls towed either on single or paired warps was analysed by Detrended Correspondence Analysis (DCA). The catches of two trawls, a semi-balloon trawl (OTSB) and a Granton trawl (GT) were very similar when towed on paired warps. Significant differences were found between the catches of the OTSB trawl towed on single and paired warps. The DCA effectively provided information on the important gradients, e.g. depth, trawl type, and indicated which species were most abundant in the different depth zones and trawl types. Detailed accounts of the abundance and biomass of different species by trawl type and depth zone are given and the observed pattern of distribution discussed.

Predation is now considered the main cause of mortality in larval and juvenile fish (Hunter, 1984) and is therefore the most important factor controlling recruitment to the adult population. Marine fish larvae are prey for many different types of predator including medusae, crustaceans and larger fish. When predatory attacks are sensed both adult and larval fish may respond by making a 'C-start', a very fast, simultaneous contraction of the trunk musculature that deforms the body into a C-shape within 20 ms (Eaton & Hackett, 1984). This startle response is mediated by the Mauthner cells, a pair of prominent neurones in the hind brain or by other reticulo-spinal cells located in the same region. As a result of reciprocal inhibition and decussation of the cell axon, stimulation on one side of the body results in contraction of all the muscle on the contralateral side.

The condition of three intertidal Paracentrotus lividus populations, which inhabit an area between Rabat and Casablanca (Morocco) known by its high wave energy and its substantial anthropogenic disturbances were described. The growth rate of the juvenile sea urchins in this intertidal zone was low compared with more sheltered populations. A sharp increase in the gonad index was observed between January and March at the beginning of a period of algal production, and was concomitant with increases in seawater temperature and food consumption rate. This gonad index increase was followed by a single spawning period occurring between March and June, probably triggered by the phytoplankton bloom induced by upwelling conditions. Larval development in all three populations was severely inhibited and could be explained, in part, by high and generalized Cu contamination throughout the region. Specific contamination of particular populations by Pb or Hg was attributed to local industries and the incomplete dispersion of pollutants in spite of the high hydrodynamics along the Moroccan Atlantic coast. One of the three populations studied showed strong indications of abnormal development; the degradation of its condition appeared to be due to the presence of a wadi (temporary river) which can seasonally reduce the salinity, directly affecting the sea urchin physiology and indirectly enhancing the metal toxicity.