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 ZOOLOGY MARINE ZOOLOGY For more than twenty years I have spent a considerable part of the summer months on board my yacht The Glimpse in the various estuaries of Suffolk, chiefly at Harwich, Mistley, Pinmill, Bawdsey, Woodbridge, Orford, and Aldeburgh, occupying much of my time in trawling and dredging, and in collecting on the surface of the water and on the banks left dry at low tide. I have never been in the district at any other season, and what I say about the marine animals relates only to the warm part of the year, from May to September inclusive. In hot weather the temperature of the estuaries is high owing to the great extent of mud banks left dry at low water, and I have known it as much as 74 deg. in the Orwell at Pinmill, whereas in winter the surface is sometimes frozen. I have never been out in the more open sea in very hot and still weather, and the highest temperature I have observed there was 67 deg., but no doubt the water in winter is warmer than in the estuaries. These differences must have a great influence on the kinds of animals met with in the different localities and at different seasons of the year. In some cases even a few weeks make a considerable difference, for some of the animals might be called annuals. There is also a great difference in different years. My observations extended from 1882 to 1903 both inclusive, and in that period there were great changes in nearly all districts. Some animals common at the earlier part were scarce or not found at the later, and the reverse, but it is impossible to say to what extent this was a periodic or permanent change. I hope that the account I now give of the numbers and species found in the above-named years may throw light on this question. At the same time it is im- portant to bear in mind that much depends on the methods used in collecting, living on board a yacht being very different from living on shore with the occasional use of a boat. Characteristic Features of the Coast In giving an account of the marine animals of Suffolk it seems reasonable to include those I have collected on the southern side of the Stour at and above Harwich, though it really belongs to Essex. This I examined much more because the northern side was farther away and less convenient for landing. I have spent a considerable time in Harwich Harbour and collected on the shore and trawled and dredged inside and 8S