Three new examples of cleaning symbiosis are recorded among the British labridae, Crenilabrus melops, Ctenolabrus rupestris and Centrolabrus exoletus. The first two have only been seen in aquaria although parasites in the stomach of C. melops caught offshore suggests cleaning activity occurs in their natural environment. C. melops has been observed in the public aquarium taking parasites from the bodies of a number of host fish most commonly the pink bream (Pagellus centrodontus). Most cleaning activity occurs after the lights are first turned on when the hosts remain stationary to be cleaned. At this time the incidence of parasites on their bodies is most obvious. Certain areas of the body are cleaned in preference to others. Details are given of cleaning symbiosis by the pipe fish Enterlurus aequoreus, Syngnathus typhle and S. acus.

The ratio of the concentrations of κ- to λ-carrageenan is shown to be related to the nuclear phase in Chondrus crispus both in culture and in nature. This ratio is low in tetrasporic plants and relatively high in the gametophytes. It was found to vary somewhat amongst samples analysed, but was always less than unity in tetrasporophytes and greater than unity in gametophytic plants. The κ/λ ratio in Gigartina stellata was high in gametophytes as in C. crispus; the tetrasporophytic phase of this species is unknown. It is suggested that the commercial quality of carrageenan can be correlated with the biological status of the harvested plants.

The locomotor roles of the myotomal muscles of fish are dependent on swimming speed. The mean maximum sustained swimming speed for coalfish (Gadus virens L.) during a 6-h period in an experimental exercise chamber was determined using a fixedvelocity technique and found to be 4 bodylengths/s. Biochemical measurements were made on the concentration of glycogen and lactate in the red muscle and white muscle at a series of known swimming speeds. Evidence is provided that red muscle alone is used at speeds below 2 bodylengths/s. The fall in concentration of red muscle glycogen was directly proportional to increased swimming speed. At speeds in excess of 2 bodylengths/s a statistically significant increase in lactate concentration occurred in the white muscle fibres. A reduction in glycogen content of the white muscle was also noted at speeds at and above the estimated mean sustained swimming speed. These results are discussed in the light of the current ideas pertaining to the division of labour between myotomal muscles in fish.

The results of decapod lipid analyses have shown that females and gravid females generally contain high levels of monounsaturated acids and that the eggs of some of these decapods are composed mainly of phospholipid and triglyceride. These are probably present mainly as energy reserves. The percentages of saturated fatty acids are not found to vary with either maturity or sex, whereas the composition of the polyunsaturated acids are affected by both sex and maturity differences. Females are generally much lower in their content of polyunsaturated acids than juveniles and males, the males showing a greater requirement for 20:5 acid compared to the females.

For the euphausiids there is a slightly different picture, the monounsaturated acids appear as the stable fraction and for Euphausia krohnii the juveniles are similar to the females in their content of the polyunsaturated acids.

Neomysis integer is quite unlike the oceanic crustaceans showing a very specific difference in fatty acid composition between the males and females, the juveniles being rather intermediate in composition.

Three levels of oxygen consumption rate are identified, viz. standard, routine and active. Animals fed above the maintenance energy requirement adjust their oxygen consumption rate to a routine level. Animals fed below the maintenance requirement reduce their oxygen consumption rate to a standard level within 35–40 days. The routine rate is seasonally variable, with high values in the winter and low values in the summer. The standard rate also varies seasonally. The exponent that relates routine oxygen consumption to body size varies from a high value in the summer to a lower value in the winter.

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.

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.

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.

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.

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.

The accumulation from sea water of 65Zn, 54Mn, 59Fe and 58Co by the mussel, Mytilus edulis, has been studied in relation to the stable element levels of these isotopes both in the sea water and in individual tissues. For all four radionuclides the greatest accumulation occurred in the stomach and digestive gland samples and further localization of 65Zn and 69Fe was demonstrated by autoradiography. As the animals were starved during the accumulation period the loss of stable elements by individual tissues was also followed. Again the most notable effect occurred in the digestive gland tissues with the exception of a large loss of iron by the foot. Autoradiography showed that after two weeks accumulation 59Fe occurs in large clusters in the foot, notable in the byssus gland area. These clusters disappear after a further two week period and may thus be secreted into new byssus threads.

A comparison has been made between the concentrations of eleven trace metals in the tissues of two species of scallops, Pecten maximus (L.) and Chlamys opercularis (L.), collected from the same area of the English Channel. Although there was considerable variation between individual animals, the mean concentrations of Ag, Co, Cr, Cu, Mn, Ni, Pb and Zn were higher in the whole body of Chlamys than in Pecten but concentrations of Al, Cd and Fe were lower. In both species, seasonal changes in the concentrations of Co, Cu, Fe, Mn, Ni, Pb and Zn were observed and, in general, the highest values were found in the autumn and winter months. These changes may be related to food supply, since concentrations were generally highest when phytoplankton productivity was low and tended to fall in the spring as productivity increased rapidly to its annual peak. Despite problems arising from individual and seasonal variation, the kidneys and digestive gland of scallops appear to have potential as biological indicators of trace metals.

The results obtained for Pecten and Chlamys are compared with those in the literature for species from the family Pectinidae.

An opening and closing net system is described in which 1 m2 and 8 m2 rectangular trawls are combined in the same framework; details of the acoustic telemetering and release equipment are included. A brief account of the application of the rectangular system to larger and to more specialized trawls is given.

1. The data for five planktonic taxa sampled during the SOND cruise (autumn 1965) by R.R.S. ‘Discovery’ in a day and a night series of horizontally towed nets have been analysed by factor and cluster analyses.

2. The factor analyses of hauls showed that there were five biologically distinct zones in the water column between the surface and 1000 m. The zones were more distinct in the day series than in the night.

3. Factor analyses of the individual taxa gave sensible groupings of species and the factor score plots gave ‘averaged’ depth distributions for each group.

4. Cluster analyses of the individual taxa gave results consistent with the factor analyses. Both methods gave groupings which fitted the zonation patterns of the hauls, except for the two zones between 100 and 460 m at night.

5. Only cluster analyses could be carried out on the total data matrices. Although satisfactory interpretation was only possible with the aid of the analyses of the individual taxa, the zonation and species groupings were again largely retained.

6. The zonation of the planktonic taxa is shown to be very similar to that described for nektonic species sampled on the same cruise.

7. The usefulness of these analytical methods is compared with the conclusions of other investigators. It is concluded that the rotation of the matrices to simple structure in the factor analysis gave a marked improvement in the ease of interpretation.

8. For this data, principal component analyses gave very similar results to the full factor analyses.