The effect of temperature on the rate of reaction catalysed by crude muscle AMP-aminohydrolase from two species of elasmobranch and two species of teleost fish has been investigated at low substrate concentration in the range of temperature 5–50 °C.

The enzyme from teleost fish shows a very broad temperature optimum around 30 °C. The reaction rate of the enzyme from elasmobranch fish is strongly dependent on temperature. The optimum temperature for the enzyme from thornback ray lies around 40 °C. Both crude and 500-fold purified AMP-aminohydrolase from thornback ray show the same temperature-dependence.

The ventricle of the heart of the plaice (Pleuronectes platessa L.) was examined in histological sections stained with Aniline blue. The ventricles from hearts from two age groups (from 3–5 years and 9–16 years as judged from otolith examination) of plaice were studied in histological section. In younger fish (3–5 years) epicardial collagen bundles form a thin (< 24–0 μm) layer and only the superficial trabeculae are partially invested with collagen bundles, those deeper trabeculae not having collagen bundles associated with them. In older fish epicardial connective tissue had increased greatly (> 120.0 μm) in thickness and endocardial collagen is much more abundant, and was observed throughout all ventricular trabeculae. Secondly, in the hearts of older fish only, an extensive epicardial vascular system was observed, as revealed by arterial and venous profiles. This vascular system was confined to the epicardium and did not penetrate the myocardium to form a vascular bed, nor was it derived from extracardiac vessels.

Spirobolbolaimus undulatus sp. nov. is described in intertidal sandy sediment from the East China Sea. The new species is characterized by six jointed outer labial setae much thicker and longer than the four slender cephalic setae, anterior and posterior pharynx bulbs, sclerotized multispiral amphid fovea, eight longitudinal rows of postamphideal setae, gubernaculum apophysis and many precloacal supplements. The new species differs distinctly from the type species Spirobolbolaimus bathyalis in the presence (vs absence) of jointed outer labial setae, eight additional small teeth, gubernaculum apophysis and many precloacal supplements and eight (vs six) rows of postamphideal setae. It differs from the other known congener Spirobolbolaimus boucherorum in the jointed outer labial setae (vs setae with smooth outline), three main teeth with eight additional small teeth (vs only three main teeth) and many distinct precloacal supplements (vs seven tiny papillate ones). We emend the diagnosis of the genus Spirobolbolaimus based on the description. Microlaimus pecticauda and Microlaimus spirifer possess two opposed reflexed ovaries, and thus are transferred from the family Microlaimidae to Molgolaimus of the family Desmodoridae: Molgolaimus pecticauda comb. nov. and Molgolaimus spirifer comb. nov.

A fragment of hedgehog was first isolated by polymerase chain reaction (PCR) from genomic DNA of Qingdao amphioxus using degenerate primers designed according to the conserved sequence in the second exon of hedgehog family. Then RT-PCR and rapid amplification of cDNA ends (3′ and 5′ RACE) were carried out using the mRNA of 18-h neurulae as template. The PCR products were sequenced and constituted a 3540 bp-long hedgehog gene, containing a complete open reading frame. The predicted protein is 415-amino-acids long, showing a high level of identity to other hedgehog proteins. The results show that Qingdao amphioxus contains one and probably only one hedgehog gene. Whole mount in situ hybridization revealed that hedgehog expressed in the prospective notochord, the notochord, floor plate of neural tube and mouth, similarly to its vertebrate homologue Sonic-hedgehog gene. This suggested that amphioxus hedgehog gene might function in the notochord induction to neural tube cells and in the development of the mouth.

Investigation of the geologic problems connected with the English Channel is no new matter. Setting aside all speculations deriving from the study of its coast-line, the first serious examination of the bed of the Channel was made by R. A. C. Austen, and his results published in the Proceedings of the Geological Society, 13 June, 1849. Although, as he states, he had examined the sea-bed with dredge and sounding-lead he has little to say as to its lithology. But none the less his work is a notable contribution to our knowledge, and his conclusions bear well the test of subsequent discoveries. Following Austen, in 1871, Delesse published his Lithologie des Mers de France, in which considerable attention is given to the Channel; and the lithology of its coastal deposits, and to some extent of the sea-bed, is considered in detail. But, valuable as this work is, its chief interest lies in the information given as to the nature of the sea-bottom, the grade and extent of the varying deposits. Austen and Delesse alike, and in agreement, point out the large areas of the Channel bed which are occupied by stones, boulders, and pebbles of some size, and argue on much the same lines as to the conditions which have formerly existed there.

In early 1956 and again in 1957 small samples of mature female Plaice Pleuronectes platessa L. were collected for fecundity estimates to be compared with Simpson's (1951) results for the North Sea populations, and the data from elsewhere that Simpson summarizes.

A simple aquarium system was used to keep large ormers collected from the wild and to rear juveniles from fertilization up to age one year. Spawning was induced by exposure to u.v. irradiated sea water and counts made of gamete production. Repeated spawning was observed in males and from egg counts it was inferred that females also undergo repeat spawning in the wild.

Juvenile ormers were reared on simple collectors up to 4 mm shell length and later in open mesh cages. There was large variation in growth rate between individuals among the juvenile ormers. After one year shell lengths varied in the range 6·2–21·o mm.

Twenty-three adult ormers (shell length 40·4–93·6 mm) were reared for eight months in a tank with a concrete shelter. The smaller ormers remained under the shelter much more than the larger ones, some of which adopted a permanent position outside the shelter. In the study period growth was greater in the smaller specimens (less than 70 mm shell length) than in the larger ones.

Porcelain crabs live in dense aggregations under boulders in the intertidal zone of northern Chile. A quantitative approach was performed to examine the distribution patterns of dominant species and to correlate it with emersion and temperature under the boulders. The study involved six tidal levels across the intertidal with six replicates each, totalling 36 samples of 0.09 m2. From the seven species found, Petrolisthes granulosus, P. violaceus and Allopetrolisthes angulosus took in 49.06%, 25.20% and 25.51% respectively, of the total number of individuals collected (N=10,631). The distribution patterns showed P. granulosus dominating in the upper levels (up to 73% of emersion and 22°C), P. granulosus and P. violaceus coexisting in the middle levels (48% of emersion and 21.6°C), and A. angulosus dominating in the lower levels (below 20% of emersion and 17.8°C). Size distribution for P. granulosus declined at its limit levels of distribution, the same tendency appeared at the upper limits of P. violaceus and A. angulosus. Temperature and emersion gradients strongly affected the species richness, abundance and mean size of the species across the intertidal, thus clearly influencing the occurrence and distribution patterns of the species studied. The ability of the upper-middle shore species to tolerate high levels of temperature and emersion is suggested to explain their distribution patterns. Size distribution differences might have been caused by biological interactions as intra and interspecific competition. A foregut content analysis revealed trophic differences among the dominant species, a result that could be related to the distribution.

Current flow regime, bathymetry and substratum angle were found to influence the density and distribution of the following anthozoan species at Lough Hyne Marine Nature Reserve, Ireland: Corynactis viridis, Alcyonium digitatum, Caryophyllia smithii, Anemonia viridis and Anthopleura ballii. Density variation was found on inclined, vertical and overhanging cliff surfaces for species found on hard substratum (Corynactis viridis, Alcyonium digitatum and Caryophyllia smithii). All species showed significant variation with increasing depth and between sites with different water flow rates.

Copula trials in Neptunea arthritica were conducted to provide possible hypotheses explaining the outcomes of reproductive interaction with regards to size differences and female resistance in the context of conflict over copula duration between the sexes. Size asymmetry predicted the outcome of copula duration to favour the largest individuals. Female resistance was expressed consistently and increased with consecutive copulas, generating variation in copula duration. When resistance was removed, copula duration increased in contrast with natural trials suggesting intense conflict. Overall, males showed a tendency to mate with large females, which represents higher rejection risk, indicating that benefits from mating with large females might offset the risk of failure against resistance. Conflict possibly stems from a ‘power asymmetry’ in which individuals of one sex could sequester control over some aspects of mating to the detriment of the opposite sex.

Antarctic krill, Euphausia superba, normally live in social aggregations (schools) but rarely aggregate in laboratory tanks. In order to study the effect of stress on solitary living we tethered krill to wooden skewers and measured heart rate both when they were held isolated from conspecifics and when they were held at normal schooling distances (∼1 body length). Heart rate did not differ significantly with sex or body size. However, intermoult krill had a significantly lower heart rate than postmoult animals. When two individuals were held at schooling distance, with one slightly higher in the water column than the other, the heart rate of the higher individual slowed significantly (106–98 beats min−1), while that of the lower individual remained the same. We interpret these results to mean that krill living solitarily are stressed but will respond to neighbouring individuals by decreasing their metabolic rate and saving energy.

Previous plankton work at Plymouth is reviewed briefly, and the limitations of the stramin ring trawl as a quantitative sampler discussed. The distribution of certain zooplankton ‘indicator’ species caught in hauls of the 2 and 1 m ring trawl during cruises in 1955 and 1957 is described in comparison with regular 2 m hauls taken throughout the same years at two stations near Plymouth.

The results support previous suggestions that ‘western’ water at Plymouth is derived from a region to the south of Ireland, i.e. from the north-west, and is not now in the direct path of the flow of water into the English Channel from the west.

An apparent northward spread of the warm-water copepod Euchaeta hebes during the past 50 years may be connected with the rise in sea temperature over the same period. It is suggested that related changes in distribution might be responsible in part for changes in the macroplankton community off Plymouth since the 1920's.

The bibliography concerning the Mediterranean Sipuncula is reviewed, particularly that from the eastern Mediterranean. Additional data are provided from macrobenthic samples collected between 1974 and 1997 in the Hellenic waters. A total of 17 species are recorded, five of which (Sipunculus norvegicus, Golfingia elongata, Nephasoma lilljeborgi, Thysanocardiacatharinae and Aspidosiphon (Akrikos) mexicanus) are reported for the first time in Hellenic waters. Three more species (Onchnesoma squamatum squamatum, Aspidosiphon (Aspidosiphon) elegans, Apionsoma (Apionsoma) trichocephalus) which are found exclusively in the extreme eastern basin (Israel, Egypt) raises the number of eastern Mediterranean Sipuncula species to twenty.

A new spionid polychaete, Malacoceros jennicus, is described from the crater of a hydrothermally active submarine volcano near Grenada in the Caribbean, Lesser Antilles Arc region. The new species is characterized by having prominent lateral frontal horns on the prostomium, paired eye spots, neurosetae that include simple capillaries, inferior sabre setae, numerous bidentate hooded hooks, and a pygidium bearing four digitiform anal cirri surrounding the anus. Worms were collected in regions of diffuse venting with a suction sampler deployed on an ROV. Specimens representing a range of sizes including sexually mature and reproductive individuals containing eggs and sperm were found. Stable isotope analysis of 13C and 15N indicate mixed feeding on photosynthetic and hydrothermal vent source material.

Depth patterns of size and abundance in a pelagic bristlemouth fish Cyclothone pallida (Stomiformes: Gonostomatidae) are reported. Sampling was conducted during the day and night at two sites in the Bahamas using a Multiple Opening and Closing Net and Electronic Sensing System (MOCNESS). All samples show peak abundance in the 500–700 m depth range irrespective of time or sampling location. The mean and variance of body length increased with depth, and size–depth patterns do not significantly differ among samples. Results suggest that these populations of C. pallida do not exhibit diel vertical migration.

Before 1888 no specimen of Tornaria, the well-known pelagic larva of Balanoglossus, had been taken off the English Coast. But on August 9th of the past year Mr. Weldon, using the surface net near the Eddystone Lighthouse, took several young specimens of Tornaria, and subsequently the same gentleman, during a cruise of a week's duration towards the end of August, captured many larger and more mature specimens of the same larva. Other specimens were taken by us up to September 21st, and in the month of August, Mr. Rupert Vallentin found several specimens in the vicinity of Falmouth.

The specimens taken on these occasions form the subject of the present memoir, and their anatomy is detailed at some length, both because of the interest attached to a form bitherto unknown to England, and because it is in some respects of morphological importance.

The specimens taken by us came from the offing, and were not taken within four miles of theshore; Mr. Vallentin's Tornaria were found close to the shore at Falmouth. As he was able to bring his back alive and preserve them at leisure in his laboratory, they are better preserved than those taken by us, since we were obliged to preserve our catch in a somewhatrough manner out at sea. An examination of Mr. Vallentin's specimens leaves me no doubt that the larva is Tornaria Kröohnii, aspecies found in the Mediterranean. The different forms of Tornariahave not been with certainty referred to their adult forms, but T. Kröohnii must belong to one of the Mediterranean species of Balanoglossus, that is to say, to B. Kowalevsltii, B. minutus, or B. claviger, species which have not hitherto been recorded from the English Channel, unless we suppose that the larva of B. salmoneus v. sarniensis, which occurs in the Channel Islands andat Roscoff, is identical with Tornaria Kröohnii.

Salema, Sarpa salpa is a commercial exploited species in the Atlantic Ocean with little available information for the essential population parameters, such as age, growth and reproduction. The present study aims to describe these parameters for S. salpa obtained off the coast of Portugal. Ages were estimated from the whole otolith readings; the minimum and the maximum ages observed were 0 and 14 years, respectively, corresponding to 5.2 and 41.4 cm of total length (TL). Whole otolith readings and back-calculation approaches were used to estimate the parameters of the von Bertalanffy growth function and the Akaike's information criterion value suggested that the second approach was the best one to describe the growth of salema: L∞ = 45.07 cm, k = 0.14 year−1 and t0 = −1.43 year. The species is a protandric hermaphrodite and the sex change process occurred between 28.6 and 40.9 cm TL. A short spawning season was identified, extending from September to November. The estimated length at first maturity for males was 24.5 cm TL, corresponding to an age of 2 years at first maturity. This species exhibited a determinate fecundity type and the relative annual fecundity varied between 462 and 2662 oocytes per gram of gutted weight.

To study the diet of the swordfish (Xiphias gladius) in the Strait of Gibraltar, a total of 176 stomachs were examined from the Moroccan artisanal fishery targeting this species, from April to September 2015. The frequency of occurrence (FO), percentage in number and in weight of prey as well as the per cent index of relative importance of prey (%IRI) were calculated to assess the diet preferences of swordfish in relation to its body size, sex and month. Our findings confirm the opportunistic feeding behaviour of swordfish. The prey items consist primarily of fish (54.6% in number and 82.7% in weight), followed by cephalopod (43.36% in number and 17.25% in weight). The Atlantic horse mackerel (Trachurus trachurus) and the southern shortfin squid (Illex coindetii) are the most important prey, with a % IRI of 47.54 and 35.04%, respectively. The results revealed that there are no significant differences in the diet preferences among sexes and size classes. However, diet composition varied significantly among months. A significant correlation was found between the body length of predator and prey size. The remarkable decrease in the fullness index (fi) from June to August suggests that swordfish were in a spawning condition, with reduced feeding.

The heart-body in Neoamphitrite figulus (Dalyell) forms a mass of tissue within the supra-oesophageal vessel almost occluding the lumen. The tissue forms a much-infolded cylinder enclosed by a basal lamina consisting of a fibrous reticulum through which the assembled haemoglobin molecules are discharged into the plasma (Dales & Pell, 1970). A function of both the heart-body and the extravasal (‘chloragogen’) tissue in polychaetes without a heart-body was established by biochemical analysis (Kennedy & Dales, 1958; Dales, 1963, 1965) to be the synthesis of plasma haemoglobin (erythrocruorin) or chlorocruorin. This was confirmed by electron microscopy (TEM) by Breton-Gorius (1963) in Arenicola, Potswald (1969) in Spirorbis, Dales & Pell (1970) in Neoamphitrite, Lattice, Myxicola, Megalomma and Sabella, and by Friedmann & Weiss (1980) in Amphitrite. It would appear that the same tissues also sequester phagocytosed materials (Braunbeck & Dales, 1984). Re-examination of this tissue by trans-mission electron microscopy (TEM) has extended our knowledge of the ultra-structure. Here we discuss these results in relation to the function of these tissues in the production of the respiratory pigments found in the plasma. Some heart-bodies of Terebella lapidaria L., Lattice conchilega (Pallas) and Cirriformia tentaculata (Montagu) have also been examined by TEM for comparison with that of Neoamphitrite figulus.

Feeding behaviour of the Japanese pygmy cuttlefish Idiosepius paradoxus, inhabiting sea grass beds, was observed in captivity. Pygmy cuttlefish preferred to feed on crustaceans and the feeding behaviour consisted of two phases, namely, attacking and eating. The sequence of attacking behaviour is divisible into three stages, namely attention, positioning and seizure. In the eating process, pygmy cuttlefish insert buccal mass into the exoskeleton of the captured crustacean. In this action the buccal mass elongates to a similar length to the first arm, and moves in various directions inside the exoskeleton and flesh is ingested as this behaviour proceeds. As a result, the empty exoskeleton remained intact when the pygmy cuttlefish finished feeding.