An investigation into the histochemistry and ultrastructure of the digestive gland of Elysia viridis has revealed the presence of two types of epithelial cells, one of which contains numerous, structurally intact algal chloroplasts. Chromatographic studies indicate that these chloroplasts are derived from the animal's specific food, the alga Codium tomentosum. Following ingestion by the animal these do not appear to be digested or excreted, but accumulate and are maintained in the digestive cells. Autoradiographic studies suggest that they may be of some benefit to the animal as symbiotic organelles. Such a phenomenon may prove to be widespread among related species of Opisthobranchia.

The use of natural plankton and other foods, and of transfer techniques during phases of mortality before metamorphosis, has made it possible for substantial numbers of herring larvae to be reared beyond this stage, thus supplying requirements for experimental work. A survival to and beyond metamorphosis of over 10% of larvae passing the yolk-sac stage (3–4% of hatched larvae) has been obtained.

The oil-spill removers BP 1002, Gamlen, Slipclean and Dasic have been tested for toxicity using the barnacle Elminius modestus Darwin. All four substances were more toxic than the laboratory detergent Teepol-L, and Kuwait crude oil. BP 1002 was the most toxic of the oil-spill removers, and Dasic the least, but all were poisonous at concentrations between 2 and 10 ppm.

Rates of respiration and nitrogen excretion have been measured for freshly caught Calanus finmarchicus (Gunnerus), Calanus hyperboreus (Krayer), Metridia longa (Lubbock) and Pareuchaeta norvegica (Boeck), from the Gulf of Maine at all seasons. The dry weight, total (Kjeldahl) nitrogen, and fat were also determined for the same animals. Seasonal variation in weight-corrected respiration and nitrogen excretion followed a similar pattern for all four species, being high in the spring and decreasing gradually through summer and fall to a winter minimum. However, the relative proportions of oxygen utilized to nitrogen excreted were different from season to season for each species. In Calanus spp., O: N ratios by atoms were highest in May, immediately after the spring bloom of phytoplankton, when the animals were rich in fat. With C. hyperboreus the ratio then declined gradually through summer and fall to a low point just before the spring bloom (March and April) when populations contained the least amount of fat; but with C. finmarchicus the ratio fell much more rapidly, remaining near 17 through summer and fall and increasing again with the production of the overwintering generation. In Metridia and Pareuchaeta the O:N ratios did not show as much seasonal variation, although there was a pronounced increase for Metridia just after the spring bloom. Both species usually had higher respiration and excretion rates and lower O:N ratios compared with Calanus spp.

Suspensions of heart-body tissue and of coelomocytes in solutions of porphobilinogen produced uroporphyrin. This affords additional evidence for the haematopoietic function of the heart-body, and for the view that the free porphyrins found there and in the haemoglobin-containing coelomocytes are formed by these tissues' own activity in haem synthesis.

A well-marked seasonal cycle in the total calcium content of the plasma was shown to occur in adult cod, Gadus morhua L., of both sexes: these changes were not found in juvenile, immature cod. The changes in concentration of plasma total calcium appeared to be associated with gonadal maturation, the period of hypercalcaemia coinciding with the maturation cycle and the plasma calcium falling to a resting level again after spawning. Seasonal changes were greatest in the female cod and it is suggested that the raised level of calcium is associated with vitellogenesis in the ripening ovary, probably under the influence of oestrogens. The cycle in the male is not yet fully understood.

Cod (Gadus morhua L.) from the Arcto-Norwegian stock were caught during their gonadal maturation cycle, and plasma samples from individual fish obtained for the determination of total calcium and vitamin A aldehyde (retinal + dehydroretinal). The concentrations of these two substances in the plasma of female cod caught during January–March were significantly correlated r = 0·728, P < 0·001, and this result supports the hypothesis that the increases in concentrations of plasma calcium and vitamin A aldehyde during the period of ovarian maturation may be controlled by the same mechanism. In September, just prior to ovarian maturation, and in October, at the beginning of maturation, there was no correlation between the concentrations of the two substances.

Stocks of adult female Pseudocalanus elongatus have been kept for the past 6 years in a laboratory remote from the sea. The techniques used in maintaining these stocks are described.

The most suitable temperature for keeping the copepods has been found to be 10 °C.

The control of pH has not been necessary.

Although an allowance of 30 ml. of sea water for each copepod is recommended, it has been found that survival is not affected by densities of up to 1 copepod/10 ml.

A dense population of Polybius henslowi Leach was recorded at the surface of the sea 15 miles off the north coast of Spain. The depth of water at this point was 1740 m. Visual observations of the swimming behaviour show that Polybius tends to swim with the body facing diagonally and backwards against the current. The space between individuals appears to be maintained deliberately and was never less than 6 ft. during daylight. Measurements show that there are at least two sizegroups present. Females represent 40% of the total of 251 animals collected, and these were at approximately the same reproductive state with the ova maturing. The males are on average 2·3 mm longer than the females. No food was found in the stomach of any of the animals taken.

The macrofauna, defined as infauna retained on a ½ mm sieve, was investigated on a flatfish nursery ground at less than 10 m depth in a Scottish westcoast sea loch during spring and late summer of 1965. The substratum consisted of well-sorted sand of 180–260 μ median diameter, and the infauna had a mean density of 755 individuals and biomass of 1·3 g dry weight/m2 on the beach and 3055 individuals and 3·7 g dry weight in the sublittoral. There was little overall change in the biomass during the period studied, increases in amphipods and some polychaetes being balanced by decreases in other polychaetes, and in Tellina for which no recruitment took place. The distribution of the fauna was studied in detail between high-water mark on the beach and a depth of 10 m below low-water springs. There were 62 species on the beach and 116 on the sublittoral sand. The number increased as the water deepened, the poorest zone being just below low-water mark. Most species showed a distinct zonation. The epifauna of the sand, which was dominated by juvenile stages of plaice and dabs, is briefly described

A photochemical reactor, using a medium power mercury arc lamp for oxidation of organic matter in sea water, is described. The decomposition of some known compounds in distilled water and in sea water, using a 380 W lamp, was followed. First order kinetics with rate constants in the range 0·2–4·0 h−1 were observed. All the nitrogen compounds tested, including urea and some of its derivatives, were oxidized quantitatively. Breakdown of phosphorus compounds was rapid, but polyphosphate esters yielded polyphosphate ion which was only slowly hydrolysed to reactive orthophosphate. If polyphosphate is to be determined, hydrolysis by heating with acid should follow the irradiation. Some samples of English Channel water contained 0·02-0–05 fig-axom P/1. as organic polyphosphate.

Analyses of sea water collected during the years 1962–65 at International Hydrographic Station E. I are given here in the same form as in earlier reports. Temperature, salinity, nitrate, phosphate, and silicate were examined. Some values of suspended carbon and chlorophyll are also included.

Salinities were markedly higher in 1965 than in the previous 3 years. All 4 years showed a low value for maximum winter phosphate levels.

The distribution, abundance, and types of micro-organisms attached to littoral and sublittoral sand grains have been described. Micro-organisms are present in colonies, ranging from 5 to 150 cells per colony. Many colonies consist of one species. Some colonies are in or surrounded by staining material, others are on flat unstained surfaces. Colonies in staining material often occur in hollows. Large areas of surface between the colonies and staining material are completely bare. Evidence suggests that abrasion may stop micro-organisms colonizing flat or convex surfaces. On grains from the sediment surface, bacteria, blue-green algae (Cyanophyceae), and diatoms (Bacillariaceae) are common. The microbial flora may alter only slightly to depths of 15 cm below the sediment surface, or may change within a few mm. It is sparse towards high water, but differs little between lower littoral and sublittoral sands. The results are discussed in relation to substrate selection by marine invertebrates.

The ‘detergent’ BP 1002 at concentrations of 1 ppm was detected immediately by the larvae of Sabellaria spinulosa which were intensely irritated by it. In loosely covered vessels, allowing the solvent fraction to evaporate, larvae seemed at first to recover but died several weeks later, the control larvae remaining active and normal. The surfactant and stabilizer fractions at concentrations of 2·5 ppm killed the larvae within a day or two.

Sand was soaked for 90 min in sea water containing the ‘detergent’ BP 1002 in concentrations of 1000 and 100 ppm (= mg/1.) and then thoroughly washed. Larvae crawling on it soon afterwards were damaged, but the toxic effect disappeared after some days.

At the junction between the scyphistoma's scyphopharynx-filament complex and its endoderm is a narrow zone of simple columnar cells. These cells can transform into amoebocytes which collect together and work their way to the aboral end of the polyp, where they secrete a cuticular encasement, thus forming the podocyst.

Light and electron microscopy, as well as histochemistry, show the podocyst to be a lamellated tanned chitin-protein complex covering the protoplasmic contents, which have a nucleated outer clear cytoplasmic layer and a yolky central zone which may be liquefied in places.

In 1962, 1964 and 1966 the author collected four species of marine triclads, viz. Procerodes littoralis (Ström), P. ireneae sp.nov., P. lobata (O. Schmidt) and Uteriporus vulgaris Bergendal in the Plymouth neighbourhood. Each species is fully described. Attention has been given not only to internal characters, as the structure of the genital apparatus, but also to external features such as the shape of the head and the pattern of pigmentation, because these external characters are sufficient for the identification of the species. Further, the geographical distribution and ecological data have been recorded for each species.

The population of Scoloplos armiger O. F. Müller at Whitstable was investigated from January 1964 to April 1965. Initially the population density was high, being over 600/m2, but the numbers sharply declined during the summer of 1964 and by the following winter the density had dropped to under 100/m.2 In addition to this decline, the population structure changed, and the overall effect was a marked reduction in the fecundity of the population. The cause of the high mortality in the summer of 1964 is unknown.

Bioluminescence has been observed in 11 halocyprid ostracod species, and the sites of secretion are described.

Bioluminescence in cypridinid ostracods has been thoroughly investigated (Harvey, 1952). However, since the original suggestion that the edge glands in the carapace of halocyprid ostracods secrete luminescent substances (Claus, 1891), only a single observation has been made confirming this suggestion on Conchoecia curta ( =clausi) (Müller, 1894).

The origins of the Marine Biological Station go back to 1885, when Professor, later Sir William, Herdman organized the Liverpool Marine Biological Committee. The Committee conducted dredging excursions in the Irish Sea, and also set up a very small shore laboratory on Puffin Island (off Anglesey) from 1887 to 1891. In 1892 activities were transferred to two small stone buildings (which still exist—see Pl. III) on Port Erin Bay. After nine years these buildings had become quite inadequate to accommodate the growing numbers both of visiting naturalists and of vacation classes which were started at Port Erin in 1897, so a further move was made to the present site at the south-west corner of Port Erin Bay in 1902.

In 1919 the control and ownership of the Marine Biological Station was transferred from the L.M.B.C. to the University of Liverpool; until 1939 the Station formed part of the Department of Oceanography, from 1939 to 1949 it was part of the Department of Zoology, and since 1950 it has formed a separate Department of the University.

The original building of 1902, whose whole seaward frontage still remains virtually unaltered (Pl. I), consisted of a central public aquarium (now room 5 on Text-fig. 1) flanked by a sea-fish hatchery (now 8, 9) and a few small research rooms (2,3,4,6,7), with two sizeable laboratories for student classes on the first floor (45–47 and 28, 30–32 on Text-fig. 2). A very valuable asset consisted of three large open-air ponds which still, after 65 years, perform their original function of maintaining a breeding stock of some 200 adult plaice.