A critical evaluation of the characters utilized in support of a report of hybridization between two sympatric European species of Pagurus is presented. These characters are contrasted with characters considered to be diagnostic for the species. Although, on the basis of present evidence, the possibility of hybridization is not wholly excluded, it is shown to be highly improbable.

Many studies have been made on the metabolism of polycyclic aromatic hydrocarbons in mammals and it has been shown that these animals can convert compounds such as naphthalene into several metabolites (see, for example, Corner & Young, 1955). Baldwin (1957) has remarked on the ability of mammals to metabolize substances that they are unlikely to meet ‘except through the medium of the laboratory’. Marine animals, how-ever, can encounter these compounds in their normal environment, considerable quantities of polycyclic aromatic hydrocarbons being present in crude oil (Boylan & Tripp, 1971), in which form substantial amounts must be released into the sea annually.

Little work has been done on the metabolism of naphthalene in marine animals, apart from studies confined – as far as we are aware – to experiments with three species of fish (Lee, Sauerheber & Dobbs, 1972) and the mussel Mytilus edulis L. (Lee, Sauerheber & Benson, 1972). Data obtained using fish were consistent with those of earlier studies with mammals in showing that the hydrocarbon is converted into hydroxylated derivatives: but no evidence of naphthalene metabolism was found in the experiments with Mytilus. Indeed, until the present work, the only species of invertebrate that has been found to metabolize the compound is the housefly Musca domestica L. (Terriere, Boose & Roubal, 1961).

The present study, using Maia squinado (Herbst), has been carried out as part of a general investigation of the accumulation of polycyclic aromatic hydrocarbons in marine food chains and was designed to establish whether a marine crustacean possesses a means of metabolizing naphthalene by converting it into soluble excretion products.

The secretory epithelium in the hypobranchial gland of Buccinum undatum L. consists of a single layer of elongated cells resting upon a basement membrane which overlies layers of connective tissue and muscle. Three principal types of cell are present. Two of these participate in the actual production of the mucinous secretion while the third is a ciliated cell. The ciliated cells also bear numerous microvilli and contain abundant microtubules and microfilaments. Neuronal contacts with the ciliated cells can be detected.

The secretion product of the gland is a loose association of acid mucopolysaccharide and glycoprotein and the cells secreting these two materials can be clearly identified. Those secreting acid mucopolysaccharide have been called acid mucin cells while those secreting glycoprotein have been called goblet cells because of their resemblance to intestinal goblet cells. The acid mucin cells are large and distended with an amorphous mass of electron luscent material. This material is strongly metachromatic in the light microscope when stained with toluidine blue. Newly secreted acid mucopolysaccharide is contained within membrane-bound vacuoles where it exhibits a whorl-like or lammelar form. This latter fine structure is lost as the vacuoles coalesce filling the cell. The goblet cells are smaller and contain discrete globular, membrane-bound, packets of electron dense material. These do not stain metachromatically. Both types of cell release their contents by rupture of the cell membrane at the epithelial surface.

The nature and the quantity of run-off into coastal waters will to a large extent influence the occurrence and distribution of a number of chemical components such as nutrient salts, organic matter and trace metals in these waters. In open coastal environments the run-off is usually quickly dispersed and diluted so that little of it remains at concentrated levels in the vicinity of the discharge point. On the other hand, if such discharge is made into closed or confined waters, the rate of dispersal will depend on the circulation pattern and the rate of flushing of the run-off. Thus in some areas where the circulation is restricted, a build up of compounds may occur which, depending on the run-off composition, may have a marked effect on the ecology of these waters. The situation may be further aggravated if the run-off includes large quantities of industrial and domestic waste.

A new species of the genus Golfingia (phylum Sipuncula), belonging to the subgenus Phascoloides Fisher, is described from the Plymouth area.

Studies of the local populations of G. (Golfingia) elongata have shown the species to vary considerably in some important taxonomic characters, in particular, the number of retractor muscles: over 13% have only two or three retractors instead of four.

Notes on, and a key to, the species of Golfingia found around the British Isles are given.

Glycollic acid is probably a major component of the extracellular organic fraction liberated during phytoplankton photosynthesis and presumably plays an important part in energy transfers in aquatic environments (Fogg, 1966). It has been difficult to investigate these possibilities, however, because of the lack of a reliable and convenient method for the determination of glycollate in natural waters. With fresh water, ionexchange resins have been used for separating and concentrating glycollate which may then be estimated colorimetrically using Calkins's method (Fogg, Eagle & Kinson, 1969). This method is time consuming and is much more difficult and laborious with sea water because of the presence of high concentrations of inorganic ions. Koyama & Thompson (1964) determined various organic acids after extraction from sea water with organic solvents but this method is also laborious and for glycollic acid yields ambiguous results. Andrews & Williams (1971) measured free amino acids and also glucose occurring in sea water in μtgl−1 concentrations by retaining them on a copper chelating resin and a charcoal column respectively and eluting them with ammonium hydroxide or 10% ethanol as appropriate.

Adult female mysids do not moult while carrying young in the marsupium. Successive larval stages can be recognized in the marsupium and this allows examination of the body length of the parents at different points in the inter-moult period. The body length of 13 species of mysids was found to have increased during the course of the inter-moult period; the average increase in length of the body is 7%. An examination of the ratio of abdomen length to carapace length at different points in the inter-moult period shows that this growth in length is accommodated in the abdomen.

A micro-analytical scheme for the determination of protein, carbohydrate, lipid and RNA levels in marine invertebrate larvae has been described in a previous paper (Holland & Gabbott, 1971). This addendum describes minor modifications to the scheme so that the level of DNA may be determined and includes a different procedure for the determination of RNA by u.v. absorption. DNA and RNA levels were determined in a number of nauplii and veliger larvae.

The hydroid of the medusa Modeeria rotunda (formerly Tiaranna rotunda) has been found to be the thecate species Stegopoma fastigiatum. The medusa has been obtained from the hydroid and reared to maturity. The stages of development of the medusa are described and figured, and its occurrence and habits are discussed. The affinities of the medusa are considered: it is shown to belong, together with the the genus Chromatonema, to the family Laodiceidae.

The systematic position of the hydroid Trichydra pudica has been uncertain because of lack of knowledge of its life-history. Medusae released from it have been reared to maturity and prove to be the species Pochella polynema. The stages of development of the medusa are described and figured. The systematic relationships of the medusa are discussed: it has the general characters of the Anthomedusae, to which the species is accordingly removed. The name Trichydra pudica has priority and should be used for both hydroid and medusa. The apparently related species Pochella oligonema should be known as Trichydra oligonema.

In the first paper of this series (Bryan & Hummerstone, 1971) it was shown that in the estuarine polychaete Nereis diversicolor O. F. Müller the concentration of copper is roughly proportional to that of the surrounding sediment. On the other hand, concentrations of zinc appeared to be relatively independent of those in the sediment and it was suggested that the level of zinc in the worm is regulated.

This paper is concerned with the biology of the sandeel, Ammodytes tobianus L., in Langstone Harbour, Hampshire; this was the main area studied in a survey of sandeel populations which are exploited for bait along the south coast of England. Aspects considered are the relative occurrence of the spawning groups; spawning seasons; population structure in terms of length, sex, age and maturity; mortality; annual growth; seasonal growth; and condition. The seasonal pattern of otolith growth and its application to the back-calculation technique, has been described elsewhere (Reay, 1972).

A. tobianus forms over 95% of the total sandeel catch in Langstone Harbour. Hyperoplus lanceolatus (Le Sauvage) is the only other species to occur regularly, but individuals of the three other British species, A. marinus Raitt, H. immaculatus (Corbin), and Gymnammodytes semisquamatus (Jourdain), have also been recorded. This pattern of species composition is also found in the other inshore areas studied along the south coast.

Records of the occurrence of postlarval stages of teleostean fishes in the plankton off Plymouth have been kept for a period of nearly 50 years. During that period noteworthy changes in the abundance of postlarvae have taken place. While in the 1920s postlarvae were very abundant in the plankton, in the 1930s they became much fewer at about the time when the herring fishery declined. Somewhere around 1965 another change took place and post-larvae became once more very abundant. There was also a marked increase in the quantity of macroplankton, which like the young fish had become much reduced in quantity in the 1930s (Russell et al. 1971).

The hydroid, hitherto unknown, of the leptomedusa Mitrocomella polydiademata has been reared from medusae collected in the Firth of Clyde. The growth and structure of the hydroid and the stages of development of the medusa are described and figured.

The meiofauna was studied over a 10-year period on a flatfish nursery ground between the high-water mark and a depth of 10 m below low-water springs.

The sediment was well sorted sand, with median diameter from 210 to 279 μ in the intertidal area and 160 to 208 μ in the subtidal. It was composed of medium rounded quartz, with the calcium carbonate content mainly 0·25 to 2·20% by weight. Porosity was 33·39% and the coefficient of permeability ranged from 1·66 to 2·33 × 10–2 cm per sec, indicating good drainage. The sand was usually over 90% water-saturated, and seldom less than 60%. The annual average concentration of particulate organic carbonwas 205 μg/g sand in the intertidal, and 684 μg/g at 5 m depth. Corresponding values for chlorophyll a were 0·75 and 4·50 μg/g.

In a previous paper (Bryan & Hummerstone, 1971) the average concentrations of copper, zinc, lead, manganese and iron in the polychaete Nereis diversicolor O. F. Müller from several estuaries draining the mineralized areas of South-West England were compared with concentrations in the sediments. Although high levels of copper and zinc were encountered in some sediments none contained high levels of manganese and, in the worms, concentrations of manganese were low and relatively constant. Other estuaries in the area have since been examined, but although thousands of μg/g of copper, zinc, lead and arsenic have been found in some sediments, concentrations of manganese exceeding 1000, μg/g have rarely been encountered. Manganese ores occur quite widely in South-West England but the scale of mining appears to have been small by comparison with that for more obvious contaminants of estuaries such as copper, lead and arsenic (Dines, 1956). However, it is thought that the field observations and experimental results described in this paper can be extrapolated to situations where much higher concentrations of manganese occur.

The blue shark is a pelagic species having a virtually circumglobal distribution in tropical and temperate seas. In the northern hemisphere, during the warmer months, they extend their range northwards in both the Pacific and Atlantic (Strasburg, 1959; Bigelow & Schroeder, 1948; Templeman, 1963). Between May and October they occur regularly and in considerable numbers around the south-west peninsula of England. Strasburg showed that in the central Pacific blue sharks are opportunistic feeders as were the other pelagic species he studied, their diet consisting mainly of squid and small fish. Bigelow & Schroeder suppose herring (Clupea harengus L.), mackerel ((Scomber scombrus L.), sardines (Sardina pilchardus Walbaum) and a variety of cephalopods to be the chief diet in northern waters, together with Squalus acanthias L. and various bottom fish on the fishing banks. In warmer waters anchovies (Engraulis encrasicolus L.), flying fish and the occasional sea bird caught resting on the water are known to occur in their diet. Bigelow & Schroeder also quote the well-known stories of blue shark following boats for offal and feeding on the carcasses of harpooned whales. Le Brasseur (1964) examined the diet of blue sharks caught by gill net in the Gulf of Alaska and in general confirmed Strasburg's observations. However, he stated that when salmon (Oncorhynchus sp.) were available in gill nets blue shark might selectively feed on them, while by-passing other readily available species occurring in their normal diet. Couch (1862) examined the stomachs of two specimens from Cornish waters, finding herring, mackerel and garfish (Belone belone L.), as well as Squalus and Conger conger L. Lo Bianco (1909) found anchovies and cephalopods in one of two specimens caught in the Bay of Naples, the other of which contained large numbers of flying-fish eggs (Exocoetus sp.).

Three specimens of Stygiomedusa fabulosa Russell, 1959, identified recently in the collections of the Zoology Department of the British Museum (Natural History) (Table 1) extend the recorded distribution of this infrequently collected genus to the Southern Ocean, and provide the opportunity of assessing the specific distinctness of S. stauchi Repelin, 1967. The specimens are the first of either species recorded from south of the tropics.

Salps swim by rhythmic contraction of the hoop-like bands of muscle which form a series of incomplete annuli along the body. The histology of these muscle bands was briefly examined by various early workers, such as Dolley (1887) and Knoll (1895), but was little known until Fedele (1932,1938) published the results of his careful investigations of a variety of species. His observations demonstrated the complexity and peculiarity of the muscle fibres forming the bands, which, as he pointed out, are in some respects comparable to those of arthropods in the arrangement of the sarcomeres. In all the species he examined, Fedele found that the muscle fibres were essentially similar in organization: a central granular core containing large nuclei was surrounded on the free borders of the fibre by a layer of myofibrils. However, this general arrangement differed in detail between different species, and Fedele recognized five types of muscle fibre, distinguishing these types upon such criteria as the fibrillar arrangement, and the disposition of the nuclei. In an earlier paper (Fedele, 1925) he had also given very clear figures of the manner in which these muscle fibres were innervated. He found that dis-crete motor end-formations occurred on the surface of the muscle bands, and that these were frequently intercalary, unlike the motor terminations of vertebrates.

Fedele's work was based upon very careful observation of living and fixed material at the light microscope level; in the present note, we extend his observations by describing the ultrastructure of these curious protochordate muscle fibres.

Ten stations were sampled in the shallow-water sand habitat of Strangford Lough using a naturalist's dredge. Sediment samples were analysed to determine median diameter (ranging from 1·13 to 3·23 ø), Phi quartile deviation (ranging from 0·17 to 0·65 ø) and Phi quartile skewness (ranging from –0·11 to –0·04 ø).

Twenty-two species of amphipod belonging to thirteen families were identified; ten species were new records for Strangford Lough and the Family Phoxocephalidae was recorded for the first time. The average number of species per station was nine and average abundance was 660 amphipods per station. The most frequently occurring species was the caprellid Phtisica marina (present in 90% of the samples); the overall dominant species was the corophiid Corophium crassicorne representing 52% of all specimens recorded.