We examined the effect of a tidal-mixing front on the three-dimensional distribution of larval fish habitats (LFHs) in the Midriff Archipelago Region in the Gulf of California during winter. Zooplankton and environmental variables were sampled from 0 to 200 m in 50 m strata. Four LFHs were defined in association with the front, two on the northern side and two on the southern side. The northern LFHs were: (1) the Mainland Shelf Habitat, located from the surface to 100 m depth on the north-east mainland shelf, characterized mainly by the presence of Citharichtys fragilis; and (2) the Wide Distribution Habitat, extending from north-west to south across the front from the surface to 200 m depth, dominated by the ubiquitous Engraulis mordax. The southern LFHs were: (3) the Eddy Zone Habitat, defined nearly on an anticyclonic eddy, with the highest larval abundance and richness from the surface to 100 m depth, dominated by Leuroglossus stilbius; and (4) the Southern Gulf Habitat, associated with low temperature waters from the southern Gulf of California, dominated by southern-gulf species (e.g. Scomber japonicus and Sardinops sagax). Despite the weak stratification and low thermal contrast (~1.5°C) across the south front compared to summer (~3°C), our results demonstrate that the frontal zone may influence the formation of planktonic habitats even during generally homogeneous periods, which may also be relevant in other regions of the world.

Mites of the family Halacaridae are abundant on the sea shore, and in the sea down to considerable depths. Their identification is not an easy matter; there is no one account which can be used to identify all the British species, and the use of any one of the general accounts of European species, such as André (1946) or Viets (1936), by itself might easily lead to misidentification.

The purpose of the present list is to record the species which have so far been found around the British Isles, and to indicate sources of reliable descriptions of each species. A list of the British species of this family was given in a general list of British Acari by Turk (1953), and this has provided the starting point for the present list; no reference to occurrence in Britain before Turk's list is given, apart from one by Halbert (1920) which was left out by Turk. Twelve of the thirty-six species in the present list were not recorded by Turk. One species, Halacarus zosterae (Fab.), recorded by Turk has been omitted because the original description is quite inadequate to decide even which genus the creature should belong to. Eight species are known from British fresh water; these have not been included in the present list.

The nematode Mesacanthion diplechma Southern is relatively rare in sediments of the Southern Bight of the North Sea and the Dutch Delta. Strangely, it is about the only free-living nematode found in the stomachs of the sand goby Pomatoschistus minutus Pallas from the same general area and even more peculiarly several hundred animals were found in sand gobies from the central part of the Oosterschelde. The large size of the nematode and its preference for the superficial sediment layers are probable causes for the first observation. For the second observation there is at present no explanation that can be substantiated. Some nematodes are known to aggregate on dead animals and possibly the Oosterschelde gobies may have been feeding on such an aggregation.

FæecalPellets of the following species are described:—

Gibbula cineraria (Linn.).

G. umbilicalis (Da Costa).

G. tumida (Montagu).

G. magus (Linn.).

Cantharus (Jujubinus) clelandi (Wood).

Calliostoma zizyphinum (Linn.).

The living morphology and infraciliature of a marine ciliate, Certesia quadrinucleata, isolated from an abalone-farming pond near Qingdao, China, have been re-investigated, and some new information about this ‘well-known’ species documented: a caudally located contractile vacuole and the highly stable ciliary pattern on dorsal side. Based on previous and present studies, an improved diagnosis is supplied: size 50–90×35–70 μm in vivo; ovoid body shape with a sharp-angled projection on the right anterior edge; adoral zone with 22–27 membranelles and a prominent paroral membrane; 11–12 frontoventral and 4–5 transverse cirri; left marginal row with 5–7 cirri; five dorsal kineties; generally four macronuclear nodules; contractile vacuole positioned at posterior end; marine.

The growth bands in the plates of the echinoid Spharechinus granularis settled on the Algerian coast were analysed. Two distinct groups of sea urchins were identified with different growth patterns related to the period of recruitment, i.e. spring or autumn. The growth rate of the autumn cohort was higher over the year following the first winter after settlement. From the second winter there was little growth difference between the two cohorts. Compared to populations from Atlantic sites, the Algerian population has a lower growth rate and reduced longevity.

The cruise, of which the zoological results are given in this report, was undertaken at the suggestion of Capt. Wharton, R.N., F.R.S. hydrographer to the Admiralty, who kindly advised me that H.M.S. “Research” was to make a fresh series of soundings off the entrance to the Channel, and put me in communication with the captain of the ship. To Capt. Aldrich I am indebted for unbounded hospitality. and attention whilst I was on board, and I take this opportunity of expressing my most hearty thanks both to him and to the officers on board for the hospitality and kindness which they afforded me, and, for the help which they gave me in the trawling operations. The “Eesearch” is a paddle vessel of 520 tons register, built last year for the express purpose of surveying, and provided with a steam winch, deep-sea trawls and dredges, and 1000 fathoms of wire rope, with accumulators and accessory tackle. The available space on board was limited; there was no separate cabin at my disposal, so Capt. Aldrich most kindly made me his guest and gave me a berth in his own cabin, and I was given as much room, as could possibly be allowed for storing my bottles and other apparatus.

A new species of tube-dwelling anemone of the genus Ceriantheopsis (Cnidaria: Ceriantharia), Ceriantheopsis lineata sp. nov., is described and can be found in fine sand or mud in the sublittoral zone (0–200 m) from Argentina to Brazil (Warm Temperate South-western Atlantic). This new species is distinguished from its congeners by a number of features, however some characters (directive tentacles, line on tentacles and length of P2) allow a conclusive identification among the other Ceriantheopsis species.

Colonies of the phlebobranch ascidian Perophora japonica were found in August 2003 in Humboldt Bay, northern California, growing on a submerged settling panel. This species has a unique terminal budding in addition to the usual subterminal stolonial budding: bright yellow stellate plaques form at the tips of many stolons. The plaques break off, float away and reattach, subsequently forming new stolons and new colonies. The presence of these plaques, and the larger size of the zooids, distinguish it from the native Perophora annectens. This is the first North American record for this species.

Based on specimens collected in the Mediterranean and Red Sea coasts of Israel, the first lessepsian flatworm (Boninia neotethydis sp. nov.) is described. The genus Boninia includes cotylean polyclads characterized by the presence of multiple accessory (prostatoid) organs. The three species described are distributed in the western Pacific (B. mirabilis) and in the Caribbean (B. antillarum and B. divae). The new species differ from congenerics in the number and arrangement of the prostatoid organs, and in the number of marginal eyes. Specimens of the new species feed on mussels, and their possible effects on Mediterranean mussel cultures should be monitored.

The ovaries of 31 franciscana dolphins (19 immature and 12 mature) by-caught in coastal waters of Argentina were examined to describe the reproductive biology. No ovarian polarity was found, both ovaries were functional and showed similar amounts of corpora. A positive trend was observed between the number of corpora and age (3–8 years old), indicating that ovulation scars are detectable for at least 4 years, and a ovulation rate of 0.39 was found for the sampled population. Age, length and weight at sexual maturity were estimated at 3.92 ± 0.09 years, 133.47 ± 11.11 cm and 32.68 ± 2.72 kg, respectively. The annual pregnancy rate was 0.36 ± 0.02 (95% CI = 0.10–0.65). The proportion of lactating and resting females found were 0.25 and 0.33 respectively. These outcomes constitute the first reproductive and life history information on franciscana dolphins from the southernmost population and are important in relation with adequate conservation management plans for this small cetacean.

Species definition is not an easy task, when considering the more than 27 known species concepts. Among them, the morphospecies concept has been one of the most applied since it is based on the use of observable morphological features. Morphometry has been used to delimitate morphospecies or similar taxa complementing the morphological observations and contributing to clarify taxonomic problems. Specimens from the sympatric species Perinereis anderssoni and Perinereis ponteni, collected from the north-eastern to southern coast of Brazil and considered synonymous by some authors, were compared through morphometric analyses for the evaluation of their taxonomic status. Morphometric analysis indicates that notopodial cirri lengths in the median and posterior regions on the body clearly allowed differentiation between the two species. Our results indicate that the number and arrangement of paragnaths demonstrate a pattern of variation that effectively differs and could be used to discriminate these two Perinereis species. This distinction was confirmed by the restricted among-population variability within each species, even when populations that are geographically very distant from each other were considered.

The study of the feeding habits of elasmobranch populations should help to elucidate the ecological role of these fishes in the marine ecosystem. Feeding habits of the apron ray, Discopyge tschudii from San Jorge Gulf were investigated. An evaluation of whether the diet of D. tschudii changes with body size, seasons, maturity stage and sex was performed using a multiple-hypothesis modelling approach. Discopyge tschudii preyed mainly on polychaetes. The consumption of polychaetes was higher in males. Also, amphipods and siphons of clams were preyed more heavily in the cold season and Munida gregaria in the warm season. Stomatopods were consumed more with increasing body size. All prey categories were independent of maturity stage. We concluded that D. tschudii is a benthic feeder.

During studies performed on the ecological conditions of Izmir Bay and its biota, a population of Fulvia fragilis was observed to have recently colonized the bay. In this study, some comments are provided on the anatomical, ecological, taxonomical and distributional aspects of the species, which was first encountered during late 2001 in Izmir Bay.

More than 127 specimens of the bivalve mollusc Idas simpsoni were collected from the skull of a fin whale Balaenoptera physalus. The skull was trawled up from a depth of 430 m near Mljet Island in the south Adriatic Sea. This is the first finding of I. simpsoni in the Adriatic Sea.

A series of results is presented on the barnacle larvae population of an area of the Firth of Clyde, over a 15-day period in the spring taken by means of a modified Hardy Plankton Recorder.

The records and observations on barnacle settlement indicate that the larval population was considerably greater than usual.

The total larval population showed no great fluctuations from day to day, and on a given day the composition of the population over a wide area was often reasonably constant.

Evidence is presented that there is no great depletion of the population between Nauplius III and cyprid stages. It is suggested that the depletion previously reported may be due in part to the method of sampling or to the conditions at the time of sampling.

During the time when the evidence indicates no depletion of population there was a heavy diatom outburst, which in this instance did not appear to interfere with the larval development.

Data are given on the density of settlement.

This study presents the first extensive investigation of echinoderm distribution in the area of mobile bottoms in the open part of the northern and middle Adriatic Sea. Five hundred and eighteen bottom trawl hauls were performed at 56 predetermined permanent stations along ten transects over different sediment types, at depths of 10 to 430 m. A total of 34 species of Echinodermata were identified (9 from the class Holothuroidea, 12 from the class Asteroidea, 4 from the class Ophiuroidea and 9 from the class Echinoidea). The list of the species, together with data on depth and sediment distribution, and the stations where individual species were found, are presented.

Two types of alvinocaridid shrimp postlarvae were taken at plume depth over the Kairei and Edmond hydrothermal vent fields in the south-west Indian Ocean. These postlarvae were superficially indistinguishable from similar postlarvae taken previously over hydrothermal vents in the Atlantic. The micronekton invertebrate taxa in the water column over the Kairei and Edmond sites were similar to those in the Atlantic. The most frequently taken deep-water fish at Kairei was an unidentified cyemid snipe eel, whereas in the Atlantic its place was taken by Gonostoma bathyphilum and species of the melamphaeid Scopeloberyx. Previous sampling over East Pacific Rise hydrothermal sites at 13°N failed to take any alvinocaridid postlarvae, but the ostracod Gigantocypris agassizi was a major component of the micronekton.

This paper is a preliminary account of a series of experiments on the hybridization of Echinoids, first commenced by one of our number (De Morgan) at Plymouth in 1909, and which will form part of a larger work now approaching completion. This will comprise the hybridization of Echinus acutus, E. esculentus, and E. miliaris, together with an account of the cytology of the hybrid crosses and the control of paternal and maternal influence by chemical means.

Two new species of dorid nudibranchs of the genus Tambja are described from the Indo-Pacific and the temperate waters of the western Atlantic. Tambja haidari sp. nov. is only known from the type locality in Senegal. This species has dark blue ground colour with yellow bands and sky-blue spots, which become real tubercles along the tail. The internal features are typical of species of the genus, with rachidian teeth that lack denticles and with a prostate slightly differentiated from the rest of the vas deferens. Tambja blacki sp. nov., from Papua New Guinea and eastern Australia, has yellow-green or green colour with black blotches. There are two large blotches on the head continuing from the inner side of the base of the rhinophores towards the rear. The notal margin is elevated and joins behind the gill in a well-developed hump. The reproductive system of this species is very characteristic because it has some features more typical of species of Nembrotha than of Tambja (i.e. vaginal gland absent, prostate spread over the bursa copulatrix and wide and elongate vagina). These descriptions bring the number of species of Tambja found around the world to 31.