1. In the pilchard (Sardtha pilchardus Walbaum) of Cornwall there is a substantial seasonal variation in the mean weight of a fish of given length. The weight is highest in late autumn and early winter, and least at the end of winter and the early spring.

2. These changes in weight are largely due to variations in the fat content of the fish, which are richest in fat at the beginning of the winter fast, and poorest at the end of it. But, especially among the larger fish, the 'residue', chiefly proteins, are drawn upon at the time of the exhaustion of the fat, and consequently at the time of minimum mean weight. The water and ash content show no seasonal variation, and therefore play no part in the observed seasonal variation in the mean weight of the entire fish.

3. The gonads have their lowest mean weight in August, increase in weight slowly throughout the winter, and are at their maximum state of development from April to July. The spawning season, as deduced from these samples, is from March to September.

4. The rate of feeding is greatest in the same months as the spawning months, namely, from April to July. From July to September the average weight of food per stomach decreases, probably not because the planktonic food is then less abundant, but because it is shared among a greater number offish. In October there is a rally in the rate of feeding, but from November to February or March is a period of fasting, when very little food is taken.

5. The food of the pilchard is exclusively planktonic. In the spring, and again in the autumn, diatoms are abundant or even dominant in the food; in the summer, copepods and Crustacea are the chief items of food.

The Pycnogonida of Plymouth have had very little attention and early records are few. Of the eight species recorded in the Plymouth Marine Invertebrate Fauna in 1904, two, Nymphon gallicum and N. gracile, are synonymous, and these two are also recorded in the 1931 edition which comprises only the same eight species. The scarcity of the records shows that little search was made for the members of this group, for on revising it at the present time it is found that thirteen species certainly occur, being five more than are shown in the Marine Invertebrate Fauna. Hodgson (1910) records thirteen species from Devonshire, but these are not all the same as the thirteen now recorded. He mentions eleven from Plymouth, three of which have not been found recently. These are Pallene spectrum, Nymphon brevirostre and Ammothea laevis.

Most fishery biologists have heard from time to time of experiments on marking fish by tattooing identification marks on them. The present usual methods of marking fish by attaching marks externally to the gill-cover, caudal peduncle, or other part of the body, have the disadvantage that a certain number of the marks are lost, and this uncertainty bedevils all those marking experiments designed to show rates of mortality or rates of capture.

Yet the only reference in the literature known to me is a very short paper by Gandolfi-Hornyold (1929). His most successful experiment consisted in marking six silver eels on the light ventral side withIndian ink (encre de Chine) introduced in the oriental fashion by a bundle of needles. Five of the six fish were alive some 6 weeks later with the marks as clearly legible as when first made. But I know of no further developments of this technique

In August 1939, I made some experiments at the Plymouth Laboratory, by the courtesy of the late Director, Dr Kemp, F.R.S., and with the help of the staff, to all of whom I would express my thanks. Some thirty-two plaice, two soles, and twenty-five rays were placed in one of the big outdoor tanks for the experiments, and were all in good condition, though they had not been fed and were certainly overcrowded

The electric tattooing needle used was bought from a professional tattooist, who also gave me a brief lesson on his art. In principle the needle is a small vibrator run from an ordinary torch battery.

Large, common, tough, the lugworm is an outstandingly good object for anatomical and physiological work. Its mode of life has not yet been clearly worked out, and one must know how an animal lives if one wishes to understand its structural and functional peculiarities. Burrowing as it does in muddy sand, the lugworm cannot be watched under natural conditions (except on the rare-occasions when itshows itself on the surface). Existing accounts of its behaviour inthe field are therefore practically confined to the form of the burrow which it excavates. The present paper attempts to synthesize, partly from field observations and partly from laboratory studies ofthe worm's activities, a coherent picture of its daily life.