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.

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.

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 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):

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.

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.

Akera bullata O. F. Müller is a tectibranch mollusc having a coiled external shell and a foot with lateral extensions used for swimming. At certain times of the year it swims actively, as was observed by Donovan, who writes that it ‘sports in its watery element with all the liveliness of a butterfly, and formed a pleasing object when kept alive in a glass of sea water’ (quoted by Montagu, 1803). Although sometimes abundant locally, it is not a mollusc often taken by the collector, even though it is a conspicuous object when swimming.

The family Otinidae is the smallest and probably the least known among the pulmonates. Thiele (1931) places it at the base of the Basommatophora, the more primitive order of the subclass Pulmonata, in the Stirps Actophila. It contains a single species, Otina otis Turton, with a geographical range confined to the coasts of the British Isles and north-west France. Its northern distribution reaches as far as the Firth of Clyde, according to Jeffreys (1869), and over the greater part of its British range it appears to follow fairly closely the distribution of the barnacle Chthamalus stellatus, which here reaches its northern limit. Otina otis is a tiny snail, and its external form is limpet-like. The shell, which is well described by Jeffreys (1869), and also by Ellis (1926), measures up to 2*5 mm in length, with a short apical visceral coil at the posterior end. It is dark chestnut brown in colour, and most resembles a minute Haliotis.

Nereis diversicolor is typically euryhaline: it is in equilibrium with normal sea water (Schlieper, 1929; Beadle, 1937), and develops hypertonicity in more dilute media which it is able to maintain indefinitely. The maintenance of this steady state is preceded by a transition period. During this there is a rapid uptake of water accompanied by a loss of salts from the worm, resulting in a fall in the osmotic pressure of the body fluids, and then a subsequent water loss which, according to Ellis (1937), is not accompanied by an uptake of salts. Worms accommodated to 25% sea water weigh about 140% of their original weight (Beadle, 1931). Beadle (1937) found that when the steady state is attained the body fluid concentration in 50% sea water approaches a value which is about 5% higher than that of the external medium, whereas in 25% sea water the concentration of the body fluid is equivalent to about 44% sea water. His worms were collected from the Northumberland coast, and concentration measurements of the body fluid were determined by Baldes's modification of the Hill vapour-pressure method. The results of Schlieper (1929) on worms from Heligoland, where they may live in a salinity as low as 4%, are based on freezing-point determinations and give a higher internal concentration in the dilute media: after 3 days in 50% sea water the concentration of the body fluid is equivalent to 68% sea water, and after 2 days in 25% sea water equivalent to 49% sea water. These varying results suggest the occurrence of local physiological races.

Nereis diversicolor is typically euryhaline: it is in equilibrium with normal sea water (Schlieper, 1929; Beadle, 1937), and develops hypertonicity in more dilute media which it is able to maintain indefinitely. The maintenance of this steady state is preceded by a transition period. During this there is a rapid uptake of water accompanied by a loss of salts from the worm, resulting in a fall in the osmotic pressure of the body fluids, and then a subsequent water loss which, according to Ellis (1937), is not accompanied by an uptake of salts. Worms accommodated to 25% sea water weigh about 140% of their original weight (Beadle, 1931). Beadle (1937) found that when the steady state is attained the body fluid concentration in 50% sea water approaches a value which is about 5% higher than that of the external medium, whereas in 25% sea water the concentration of the body fluid is equivalent to about 44% sea water. His worms were collected from the Northumberland coast, and concentration measurements of the body fluid were determined by Baldes's modification of the Hill vapour-pressure method. The results of Schlieper (1929) on worms from Heligoland, where they may live in a salinity as low as 4%, are based on freezing-point determinations and give a higher internal concentration in the dilute media: after 3 days in 50% sea water the concentration of the body fluid is equivalent to 68% sea water, and after 2 days in 25% sea water equivalent to 49% sea water. These varying results suggest the occurrence of local physiological races.

There is a considerable literature on the ecology of intertidal animals and a growing one on the sublittoral fauna. Largely because of the difficulty of taking samples in very shallow water, little attention has been paid to the continuation of the intertidal zonation below the low-water mark. Although incomplete in some respects, the results of the present survey are published, partly to help bridge the gap between studies of sublittoral and intertidal faunas, partly because it is unlikely that this survey will ever be completed and partly because the intertidal fauna of one of the bays is particularly well known. The work was begun in 1938 by one of the authors (A.M.) but was discontinued at the outbreak of the late war. Since 1949 further collections have been made and the identity of most of the species taken in the earlier sampling has been checked. The collections of animals and a full account of the results have been deposited in the Marine Laboratory at Millport.

There is a considerable literature on the ecology of intertidal animals and a growing one on the sublittoral fauna. Largely because of the difficulty of taking samples in very shallow water, little attention has been paid to the continuation of the intertidal zonation below the low-water mark. Although incomplete in some respects, the results of the present survey are published, partly to help bridge the gap between studies of sublittoral and intertidal faunas, partly because it is unlikely that this survey will ever be completed and partly because the intertidal fauna of one of the bays is particularly well known. The work was begun in 1938 by one of the authors (A.M.) but was discontinued at the outbreak of the late war. Since 1949 further collections have been made and the identity of most of the species taken in the earlier sampling has been checked. The collections of animals and a full account of the results have been deposited in the Marine Laboratory at Millport.