Available data concerning the taxonomy, biology, ecology and biogeography of the genus Haploops is presented. The genus, represented by 15 valid species, is typically associated with deep and cold waters. Haploops is confined to the Arctic, north Atlantic and north Pacific Oceans with the exception of two Tasmanian species. Phyletic relationships show four principal groups of species, but there is no clear correlation between these groups and their biogeographical distribution. The biology of Haploops is typical of the biology of a cold-water amphipod. The distribution and the biology of Haploops is contrasted with that of Ampelisca, another genus of the family Ampeliscidae.

In freshly collected Naesa bidentata there exists a clear dependence of respiration rate, measured in sea water, on the tidal cycle, with the maximum occurring at high tide, the minimum at low tide. In specimens that had spent 1–2 days in the laboratory the tidal rhythmicity is less pronounced due to a lowering of the Qo2-values at high tide and at the beginning of experiments. This is interpreted as reflecting differences in nutrition between freshly collected and laboratory specimens.

In the Plymouth district there are five or six species belonging to the Galatheidse, one Munida, and four or five Galathea. The species occurring are the following :—

Munida banffica (Pennant).

Galathea strigosa L.

Galathea dispersa Kinahan.

Galathea nexa Embledon.

Galathea squamifera Leach.

Galathea intermedia Lilljeborg.

Chlorophyll from the phytoplankton at station Ei was examined from September 1951 till August 1952, from o to 50 m. The minimum was in June, i-8 mg./m.3, and the maximum 342 in March, both surface samples. The maximum 50 m. sample contained 18-4 mg./m.3 in April. The winter minima were 4-6 and 43, surface and bottom, in November. Converted to water column (70 m.) values, over iog./m.2 is obtained for the wet weight of phytoplankton for September and March, the April maximum and the June minimum being 132 and 015 g./m.2. A comparison with the production obtained from phosphate analyses suggests that the phytoplankton crop each month is rapidly devoured.

Exact proportionality was found between concentration and absorption in a chlorophyll band up to 40 mg./l. and a moderate error up to 80 mg./l. The spectral absorption curves have been given for pure cultures of phytoplankton and for cells filtered out of sea water. The chlorophyll in such extracts, made with 80% acetone, is stable when kept in total darkness.

The collodion disks containing suspended clay arid the algal cells may show a surprising variation in their colour intensity, from dark grey to a very faint tint, even though obtained from sea water about 20 miles from land and over 70 m. in depth. The surface may be far darker than 5, 10 or 15 m. samples.

The botanical composition of the water was studied by allowing the algae to multiply in diffuse light after enriching the water chemically. Eight species of Chlorophyceae, and one species each of the Chrysophyceae and Dinophyceae were recorded. Of the Cryptophyceae one winter sample from 50 m. gave a nearly pure growth of Hemiselmis rufescens Parke. The diatoms Melostra borreri, Nitzschia closterium and Navicula sp. occurred commonly.

Ability to tolerate low salinities has been compared in homozygous adult females of the trifasciata and violacea forms of the polymorphic copepod Tisbe reticulata from Chioggia (lagoon of Venice). Both forms appear to be equally capable of tolerating sea-water concentrations of between 100 and 33 %. Further comparison with the trifasciata form of T. reticulata from Plymouth and with three different geographical populations of Tisbe furcata has shown that these copepods are rather less tolerant.

A study of ionic regulation using the isotopes 22Na, 42K and 137Cs has shown that in diluted sea water T. reticulata does not control the body Na concentration but does control the K concentration. Exchange rates for 42K and 137Cs are higher in the violacea than in the trifasciata forms of T. reticulata from Chioggia and the difference may have an adaptive nature although its significance is not clear. With regard to 42K, the difference between the two polymorphic forms from the same population of T. reticulata is greater than that between the three different geographical populations of T. furcata. This serves to add more emphasis to the fact that colour polymorphism in T. reticulata can be associated with other processes.

A study of the intertidal macro-invertebrate fauna of south east England was carried out as part of the investigations funded by the Department of the Environment of the likely ecological implications of the Maplin development proposals. The main aim of this study was to determine the potential food resource the invertebrate populations represent for the large numbers of wading birds which overwinter in this region. This article will concern itself solely with aspects of the invertebrate populations, the relationships between the waders and their invertebrate food supply will be presented separately (Kay, Blindell & Goss-Custard, in prep.).

Distribution and abundance of the macrobenthic fauna was studied in the intertidal and subtidal soft-bottoms of the Ensenada de San Simón (north-western Spain). Depth and grain size were the most important factors in determining patterns of distribution of the macrozoobenthos. A reduced Macoma community was present in the inner area of the inlet structured in two facies subdivision in the community that does not affect its qualitative composition: the first one was in intertidal areas associated with meadows of the sea grasses Zostera noltii and Z. marina and defined by the dominance of Hydrobia ulvae; the second facies in intertidal sediments was characterized by the dominance of Tubificidae and nematodes and Pseudopolydora paucibranchiata. The poverty of these bottoms in number of species can be due to salinity fluctuations and human activities developed in the area. Subtidal bottoms were characterized by a Syndosmya(=Abra)alba community. Two facies were detected: one facies located in shallow subtidal bottoms with H. ulvae and Thyasira flexuosa as characteristic species, and a second facies in deeper areas, characterized by the polychaetes Ampharete finmarchica, P. paucibranchiata, Aphelochaeta marioni, Melinna palmata and Paradoneis lyra.

The vertical and horizontal distribution on the shore and the distribution between the host shell species, is described for a number of species of green shell-boring algae. A list is given of the records made in Britain for shell-boring Codiolum stages and for Entocladia perforans. An account is given of the sequence in which shell-boring algae attack Spirorbis worm tubes in the Isle of Man.

INTRODUCTION

Parasite-induced excess growth, or gigantism, has been reported in several mammals (reviewed by Cheng, 1971) and a fish (Summerfelt & Warner, 1970). Work on invertebrates has centred on size increase in gastropod molluscs associated with infections by larval trematodes (reviewed by Cheng, 1967, 1971). Among these the results have been variable, with some host species showing real gains in body size (soft tissue) (Rothschild & Rothschild, 1939), others initial gains with later stunting (Pan, 1965), and still others gains only in shell thickness (Cheng, 1967). Parasitic castration in other invertebrate groups, not necessarily accompanied by gigantism, has been reviewed by Kuris (1974).

A new type of Nauplius belonging to Meganyctiphanes norvegica is described.

Attention is drawn to irregularities in the development of the furcilia forms in which particular stages are sometimes omitted.

It is suggested that in the larval history of M. norvegica in common with other Euphausids there is an indication of evolutionary progress in the group Euphausiaceæ.

A number of species of the family Pectinidae (Lamellibranchia, Mollusca) are of considerable commercial importance in many parts of the world. Many of these are being reared in laboratories and hatcheries and this has made easier studies of cytogenetics using eggs and embryos, and ultimately will make studies of their genetics feasible. Recently, simple squash techniques have provided a fast and reliable method for obtaining chromosome numbers from eggs and embryos of several bivalves including Mercenaria spp. (Menzel & Menzel, 1965), Ostrea lurida and Crassostera gigas (Ahmed & Sparks, 1967), Mytilus spp. (Ahmed & Sparks, 1970), and Crassostrea spp. (Menzel, 1968). In 1967, Longwell, Stiles & Smith published the karyotype of Crassostrea virginica obtained from embryos which had been treated with colchicine.

A description is given of a glass cloth surface which prevents the settlement of larvae of Balanus crenatus and Pomatoceros triqueter, whilst not affecting that of Tubularia larynx. A number of possible causes for this are examined, and its relation to other work on the settlement of sedentary forms is briefly considered.

of winter phosphorus have represented differences in numbers of 6-month-old pilchard larvae; the winter phosphorus provides the link between herring recruitment and numbers of pilchard eggs, suggesting that there has been competition between the herring and pilchard stocks, in their juvenile stages. Thus it is suggested that the Plymouth herring fishery failed in competition with the pilchard stock and that the other biological events which took place in the early thirties were a consequence of this postulated competitive change.

Although adult Norway lobsters are extremely common on the southern part of the Northumberland coast, there were no records of the taking of larvæ of the species in this part of the North Sea until the Plankton Investigation now being carried out at Cullercoats (1) was commenced.

During the period 1921–23 a few specimens were taken from time to time in the ordinary plankton hauls, but the best catches of Nephrops larvæ were obtained from the young fish trawl used at a number of stations in 1922 arid 1923. It is, therefore, chiefly on the material from the last two years' samples that the following observations are based.

All three of the larval stages have been obtained, together with a single post-larva, but the majority of our specimens are second and third stage larvæ.

The Continuous Plankton Recorder (CPR) survey has collected plankton samples from regular tracks across the world's oceans for almost 70 y. Over 299,000 spatially extensive CPR samples are archived and stored in buffered formalin. This CPR archive offers huge potential to study changes in marine communities using molecular data from a period when marine pollution, exploitation and global anthropogenic impact were much less pronounced. However, to harness the amount of data available within the CPR archive fully, it is necessary to improve techniques of larval identification, to genus and species preferably, and to obtain genetic information for historical studies of population ecology. To increase the potential of the CPR database this paper describes the first extraction, amplification by the polymerase chain reaction and utilization of a DNA sequence (mitochondrial 16S rDNA) from a CPR sample, a formalin fixed larval sandeel.

The populations of Buccinanops monilifer (Gastropoda: Nassariidae) from two different sites, Mar del Plata (Buenos Aires province) and a close non-polluted locality (Mar Chiquita), are compared in their imposex indices and reproductive parameters. In Mar del Plata, a beach nourishment (sand filling) remobilized sediment from the harbour area during 1999; our results show high imposex percentage and an increase in relative penis size index during and after this beach filling event, in contrast with the Mar Chiquita population that showed nil values during this study. Comparisons of reproductive parameters between both populations showed significantly higher frequency of spawning females and number of egg capsules per female in Mar Chiquita, while female size and number of eggs per capsule did not differ. Females from Mar del Plata that did not succeed in spawning showed higher imposex values than spawning ones. Sex-ratio was not significantly different from 1:1 in any of the sites (although male-biased in Mar del Plata and the opposite in Mar Chiquita). We found no malformations or abnormalities during intracapsular development in the imposexed population. Alternatively, we found evidence that suggests that B. monilifer intracapsular development includes the occurrence of intracapsular embryonic cannibalism of other smaller embryos, which was not previously known in this genus, and that complements adelphophagy (feeding on nurse eggs feeding).

The distribution of free neuromasts and the formation of the lateral line canals are described for two species of flatfish (plaice, Pleuronectes platessa L., and turbot, Scophthalmus maximus L.) during development from the bilaterally symmetrical larva to the bilaterally asymmetrical adult. On hatching plaice have three free neuromasts per side compared with six in turbot. After feeding is established plaice have 40–60/side compared with 20–25 in turbot. During development the ‘hillock’ of sensory cells increases in size and the cupulae grow in length. Canal formation starts later in plaice than in turbot. During metamorphosis the canal system becomes more concentrated in the upper (eyed) side of both species, but lateral line canals occur both on the head and body regions of the blind side. In plaice the tubes leading from the canals to the surface have typically one pore/tube, whereas in turbot there is much branching with 8–10 pores/tube.

The diet of greater amberjack Seriola dumerili (Carangidae) in the Gulf of Gabes (Tunisia, Mediterranean) was described from analysis of stomach contents of 290 specimens fished between June 2004 and May 2006. The index of vacuity (%VI) was relatively low (37.9%) and differed significantly across size classes. Seriola dumerili is an opportunistic predator that consumes mostly pelagic organisms; benthic prey were also examined in small proportion. The diet was quantified using the frequency of occurrence (%O), numerical abundance (%N), weight (%W) and the index of relative importance (IRI and %IRI) for each prey taxa. The most important prey were teleosts (%IRI = 99.61); molluscs and crustaceans were found occasionally (%IRI, 0.38 and 0.01%, respectively). Among teleosts, Clupeidae were also the dominant food items in number (%N = 36.06%) and then in frequency of occurrence (%O = 36.7%). In term of weight, Sparidae were the most abundant prey (%W = 36.5%). There is no significant difference between male and female diets. Seasonal differences in the diet components were observed.

An account has been given (Harris, 1972b) of the distribution of interstitial harpacticoid copepods on an intertidal transect at Whitsand Bay, E. Cornwall. The present work describes seasonal changes observed in the copepod species populations over a period of 2 years, from May 1968 to May 1970. Changes in population density and vertical distribution are described, and the relationship between these changes and the physical environment are discussed. A full account of the reproductive activity and lifecycles of the copepod species will be given later (Harris, 1972d). The only detailed accounts of seasonal cycles of individual intertidal harpacticoids are those of Lasker, Wells & Mclntyre (1970) for the sand-dwelling benthic copepod Asellopsis intermedia (T. Scott) and of Barnett (1968, 1970) for two species of Platychelipus Brady on an intertidal mudflat.

Megafauna from the Charlie–Gibbs Fracture Zone (northern Mid-Atlantic Ridge) based on video observations from submersibles was analysed. Species composition was examined, frequency of species occurrence on the fracture wall and its base (depth range from 1740 m to 3100 m) and density of megafauna in the depression at the fracture zone bottom (4200–4500 m depth) were evaluated. At depths between 1700 and 2500 m hexactinellid sponges were most common and diverse. Deeper parts of the wall and its base were dominated by anthozoans (especially gorgonian corals) and echinoderms. A set of dominant species in the lower bathyal in the study area was different from that on the lower continental slope in the north-east Atlantic (Porcupine Seabight). An important contribution to local species richness of ‘rare’ species was demonstrated. The elpidiid holothurian, Kolga nana, occurred at high density in the abyssal depression.