From 1922 until the outbreak of the 1939–45 war, the Association's Laboratory at Plymouth was well served by the research vessel Salpa—a converted Lowestoft steam drifter having an overall length of about 95 ft. In 1939 Salpa was taken over by the Admiralty for naval duties and was not put back into service by the Association on her release after hostilities ended. Her place was taken by a 90 ft. motor fishing vessel on charter from the Admiralty and named Sabella. This vessel was only partially converted for research work and was handed back to her owners when Sarsia came into service at the end of 1953

The concept of external metabolites in the sea, which has received support from biological investigations, invites chemical corroboration which, until recently, has not been forthcoming. Separations of organic matter from filtered sea water using a variety of methods are reported and a preliminary assessment made. Organic residues obtained from different open sea sources by adsorption on carbon give rise to different paper chromatogram patterns. Certain organic components of a carbon adsorbate contain substances which affect the growth of a number of marine phytoplankton organisms. Further research is planned employing methods of isolation and chromatography of the dissolved organic matter from different sea waters and the assessment of biological activity of certain fractions by means of common marine organisms. Some aspects of the significance of biologically active compounds in the sea are mentioned.

The death of George Parker Bidder in his 91st year on 31 December 1953 has removed our last personal link with the days of the early development of the Marine Biological Association and its struggle for existence between the end of last century and a few years before the First World War. After the death of E. J. Allen in 1942 the only other survivor who had played a major part in the story besides Bidder was Walter Garstang, who died in 1949. Apart from those like Allen and Garstang, who were directly responsible for carrying out the work for which the Association was founded, no one contributed more vitally to its final success than Bidder, whose shrewd counsel and wise benefactions were undoubted factors in the survival of the Plymouth laboratory. In these days of recognition by the Government of the needs of science it is not easy for us to appreciate what the difficulties must have been for those who had to prove to an unresponsive audience that marine biological research was worth while. Those men were remarkable in their generation, and one of the most remarkable of them was G. P. Bidder.

A description is given of the commonest sublittoral algae and sessile animals found on rock at Stoke Point Reef and at the E. Blackstone rock near Dartmouth to a maximum depth of 28 m. The E. Blackstone fauna resembled that of Plymouth Sound. The marked change which has been found is ascribed to the greater turbidity of the water near Dartmouth and the increased shelter from wave action.

The main purpose of the work described in this paper was to find a humane way of killing crabs for eating, but the method that resulted from the investigation is applicable also in the biological laboratory, unless it is necessary that the nerve ganglia should be intact.

In previous papers (Southward, 1950, 1951 Southward & Crisp, 1952, 1954 a, b: see also Kitching, 1950 Moore & Kitching, 1939) it has been shown that the geographical distribution of several common intertidal animals in Britain is related to the temperatures prevailing in the different regions. Species of generally southern distribution in Europe are commonest on, or restricted to, the south and west coasts of Britain, where temperatures are higher, while those species of essentially northern character are commoner in the north and east where the temperatures are lower. Where species of northern and southern distribution occur side by side in the same habitat, and are in competition, it seems important to know the range of temperatures over which processes such as feeding and respiration can be carried out, as well as the often narrower range of temperatures within which breeding can take place (cf. Orton, 1920). For example, the two common intertidal barnacles of the European coasts, Chthamalus stellatus (Poli) and Balanus balanoides (L.), occur side by side only in Britain and Northern France, where they reach the northern and southern limits respectively of their distributions. From the distributions it can be inferred that the vital activities of the two species are keyed to different temperature ranges. This implies that for each species there is an optimum range of temperature, above or below which the species becomes less efficient at feeding, respiring or reproducing. Where the two species occur side by side, there may be periods of the year when one of them is living outside its optimum range, and is at a disadvantage compared with the other species.

During a study of the relation between temperature and cirral activity of barnacles, reported in Part I of this series (Southward, 1955), specimens for investigation were collected from those habitats and tide-levels where the particular species was most abundant. However, it is possible that some variation in behaviour may arise from local environmental factors such as tide-level and degree of exposure to wave action, and experiments were carried out to test this possibility.

A recent study by Fretter & Graham (1949) has shown that members of the family Pyramidellidae are ectoparasites, each species feeding on a particular host, usually a tubicolous polychaete or a lamellibranch, by piercing the body wall with the buccal stylet and sucking blood, and perhaps tissue debris, by means of the buccal pump. A list of hosts, each with its specific parasite, was given.

Subsequently, Cole (1951) recorded the presence in oysters of a species, Odostomia eulimoides Hanley, which had been observed by Fretter & Graham, and recorded previously by Jeffreys (1867), as feeding on Pecten maximus (Linné) and Chlamys opercularis (Linné). The Odostomia were lodged in small pockets inside the ventral margin of the shell of 2-year-old native brood oysters dredged from near Paglesham in the River Roach, Essex. The pockets were formed as a consequence of the withdrawal of the mantle in response to the irritation caused by the proboscis of the parasite during feeding.

The jelly-fish Aurelia aurita possesses external and internal ciliary currents that play a large part in food collection and in the transport of food, reproductive products and excretory matter.

Adults feed on relatively small organisms, which are collected in mucus on all external surfaces and eventually passed to the inner surfaces of the oral arms.

The inner surfaces of the oral arms bear two ciliated tracts which operate simultaneously in opposite directions. The lateral tract carries food materials proximally towards the gastric pouches, but is capable of rejecting inedible matter. The basal tract carries excretory matter distally, away from the gastric pouches and canals to the exterior.

Rejection reactions are also found in the gastric pouches and radial canals, parts of which have currents moving in opposite directions on the roof and on the floor. These opposing currents appear to be derived from the system in the ephyra stage, where the circulation in the wide gastric cavity and blind-ending canals is maintained partly by centripetal currents on the floor and centrifugal currents on the roof.

The directions of the main currents remain constant throughout the larval stages to the adult, although slight variations are introduced by morphological changes. The currents also remain the same during spawning, when the eggs and sperm leave the gastric pouches by the normal excretory path.

Many of the ciliary currents found in Aurelia are present in other semaeostome and rhizostome medusae, but only in Aurelia do the umbrella surfaces and currents play a large part in food collection.

One of the difficulties encountered in the use of fresh water organisms for the assay of vitamin B12 of marine origin is the elimination of salt from the extracts. This has suggested that a marine organism might be used with advantage. Indeed on several occasions marine or supra-littoral species have been proposed as possible assay subjects, but acceptable techniques await development (Lewin, 1954; Droop, 1954; Sweeney, 1954). Monochrysis lutheri, a supra-littoral euryhaline species, has advantages over others in being small, robust and giving heavy yields in synthetic media. The method employed in some Monochrysis assays carried out in the early spring of 1954 will be described.

The sheltered beach of Kames Bay, Millport, Isle of Cumbrae, Scotland has been the scene of several important studies on intertidal zonation (Stephen, 1929; Elmhirst, 1931; Watkin, 1942). The last paper is most comprehensive and records in detail the zonation of over twenty species of animals. In the course of the present study I have found Watkin's account very accurate, but incomplete in respect to salinity variation in the interstitial water of the sands. My attention was initially directed to Kames Bay in a search for a population of Nereis diversicolor O. F. Müller inhabitating an essentially ‘marine’ environment in respect to salinity. The suitability of Kames Bay was suggested by a statement of Watkin (1942, p. 558):

Kidneys of Lophius piscatorius L., perfused with heparinized blood, respond to a high tension of CO2 in the blood by a drop in urine flow and in their capacity for concentrating Mg. At the same time, but independently, CO2 reduces the blood flow. Both cyanide and fluoride may stop or reduce water secretion and Mg concentration, according to the concentration used, showing that both these activities are dependent on aerobic processes and presumably on the integrity of the carbohydrate cycle.

The results of analyses of water from the International Hydrographic Station EI during 1954 are discussed. The seasonal variation is shown, in which it appears that consumption of nutrients in the spring outburst of plants was: phosphate 0.37μg atom P/l., total phosphorus 0.26μg atom P/l., silicate 2.49μg atom Si/1., these figures being means for the whole water column. Unusual changes in silicate concentrations between January and February,and between August and September, are ascribed to changes in the water mass at the station. This conclusion is supported by the temperature, salinity and phosphate.observations.

Several cyphonautes larvae (Polyzoa Ectoprocta) have been distinguished and described (Lohmann, 1911; Marcus, 1940; Thorson, 1946), but few have been seen to metamorphose, thus Unking the late larva with the adult. Three, belonging to the suborder Cheilostomata, which have been observed to do so, are Cyphonautes compressus into Electra pilosa L. (Schneider, 1869; Barrois, 1877; Kupelwieser, 1905–6), Cyphonautes occidentalis into Membranipora villosa, (Robertson, 1908; O'Donoghue, 1927) and an unnamed cyphonautes into Nichtina ( = Membranipora) tuberculata (Hastings, 1929, pp. 706–7).

The heart nerves of Praunus flexuosus Leach ( = Macromysis flexuosa White) have been stained with methylene blue applied in various ways. As a rule the animals were injected with a solution prepared immediately before use by mixing 1 part of 0–5 % solution of methylene blue in distilled water or of rongalit white with two parts of sea water. The injection was made into one of the posterior segments of the abdomen with the needle pointing forwards. When three or four animals are treated at the same time, usually in at least one of them the staining reaction takes a satisfactory course and its progress can be observed under the microscope, owing to the transparency of the tissues. In a few minutes after the injection some of the nerves are already visible. Later the coloration becomes more general and more intensive, but soon begins to fade out and can disappear completely.

Most of the naturalists of the nineteenth century were attracted by the tube-building abilities of the terebellid polychaetes rather than by their feeding behaviour. As Dalyell (1853) says in his Powers of the Creator, referring to terebellids: ‘All are architects, nor of contemptible skill, as we shall find on contemplating their mechanical labours.’ Perhaps the best known English work dealing with this subject is the paper by Arnold Watson (1890) on the tube-building habits of the sand mason (Lattice conchilega), and while concerned mainly with tube building, the paper does include some observations on the feeding habits. Earlier, Gosse (1854) had recorded his observations on the behaviour of terebellids, and some additional information may be found in Quatrefages's Treatise of 1865. The first serious attempt to find out more about the morphology and histology of the gut in terebellids was made by Claparède (1873), and this work was published posthumously in his monograph on the Polychaeta Sedentaria.

The cyphonautes larva found in certain ectoproct Polyzoa is considered to be most probably a primitive larval form, which has been lost in viviparous species, the larvae of which are degenerate in varying degree and settle within a short time. The cyphonautes is truly planktonic and has a free swimming Life of some length—of 2 months according to Marcus (1940, p. 334)—and unlike the other known larvae of the group, has a functional alimentary canal. It obtains its food by maintaining a continuous current of water through the mantle cavity or vestibule, its ciliary mechanism being organized on a plan somewhat resembling that of bivalve molluscs, with an inhalant and an exhalant chamber with interposed ciliary ridges bearing current-producing and food-conveying cilia. As in lamellibranchs the organ creating the water and food currents is separated by a considerable interval from the mouth. In lamellibranchs this interval is bridged by the palps and the oral grooves; in the cyphonautes by the ciliated tract of the funnel. The cyphonautes being a larval form of probably archaic character its method of feeding is of particular interest.

A bacteria-free culture of the important centric diatom Skeletonema costatum has recently been established at Millport, and some exploratory nutritional experiments have been carried out with it. S. costatum is a photo-autotroph whose autotrophy is, apparently, limited to cobalamin (vitamin B12).

Details concerning isolation and maintenance of S. costatum differ from those already published (Droop, 1954a, 1955) only in the matter of pH control, a vital factor in the successful culture of this species whose range of tolerance is narrow (pH 7–5–8–5).

This paper aims at describing the external morphology of seven British species of Idotea from the functional and developmental aspects, thus revising earlier descriptions, such as those of Collinge (1917), which were based largely on adult specimens. Limitations of earlier descriptions are apparent, but some characters can be sifted from the older literature and combined with characters emphasized in this paper to give a schematic description of the seven species.

Our published work has shown that the northern euphausiids, Meganyctiphanes norvegica, Thysanoessa raschii and T. inermis, contain much higher concentrations of vitamin A than we have found in any other marine Crustacea (Kon & Thompson, 1949a; Batham, Fisher, Henry, Kon & Thompson, 1951; Fisher, Kon & Thompson, 1952, 1953, 1954). In the antarctic species, Euphausia superba, the concentration of vitamin A in samples taken from the alimentary canals of baleen whales (Thompson, Ganguly & Kon, 1949; Kon & Thompson, 1949b) was similar to that found in Meganyctiphanes norvegica from the gut of arctic baleen whales (Fisher et al., 1952), but both were very much lower than in free-swimming M. norvegica. No corresponding free-swimming specimens of Euphausia superba had been analysed.