MARINE ZOOLOGY Ceratium The Orwell is occasionally characterized by the occurrence of a large number of the small Peridinean Ceratium. This multiplies to a remarkable degree in the dock at Ipswich so as to completely alter the colour of the water. In fine sunny weather it rises to the surface and is more or less drifted into the sheltered upper corner, so that the whole looks of a peculiar coffee colour. By careful division and counting I found that near the surface the water may contain several millions per gallon and the bottom only about one-twentieth of that number, and that when cold and dull the surface may contain only 40,000 per gallon. This is the only locality in which I have seen anything of the kind. I. PROTOZOA Noctilura mi/iarii. The number of this per gallon of water varies enormously in different places and in different seasons and in different years. Sometimes they are very few, but on one occasion the average number from top to bottom in Harwich Harbour was about 4,000 per gallon II. PORIFERA {Sponges) I. CALCAREA II. SILICEA Leuctsoltnla lacunsia, Johnston. Dredged in the Wallet by Mr. H. W. Unthank — iofryciJei, Ellis & Solander. Found in the Orwell near Pinmill and in the Wallet Specimens of G. coro- nata and compreaa, which attain extra- ordinary size, were procured by Rev. W. B. Clarke in the Orwell (see Bowerbank Brit- ish Spongtadae), (A.M.N.) Grantia coronata, Ellis & Sol. — compresia, O. Fabr. Chalmo oculata, Pallas. In the Orwell near Pin- mill and in Harwich Harbour Hatuhondria panicea, Pallas. Previous to 1895 this was very abundant in the Orwell near Pin- mill, and is more or less common in other places Isodictya fucorum, Bowerbank. Dredged in the Wallet by Mr. Unthank — palmata, i Bowerbank. Found in the Wallet by Mr. Unthank C/iona celata, Grant. Found in oyster shells, into which it bores and does much in- jury III. COELENTERATA {Jellyfish, Sea Anemones, &c.) I have not myself collected the more minute species, but Mr. Wm. Cole lent me a collection made by Mr. G. H. Hope in the neighbourhood of Harwich, and the species have been identified by Dr. Walter Garstang. I. HYDROZOA 1. Hydroid Zoophytes Coryne vagitia/a, Hincks. Found by Mr. Hope in June and July Tubularia larynx, Ellis & Sol. I have often ob- tained this from the bottom of my yacht after lying in Suffolk waters — indivisa, Linn. I am almost certain that I have found this in Suffolk, but it does not appear to be common, and 1 have not seen it lately I 89 I. HYDROZOA (««/.) I. Hydroid Zoophytes (cont.) ObeRa gelatinosa, Pallas. I have obtained several tine specimens from the Orwell Sertukrell: polyxomas,]Jxin. Found near Harwich by Mr. Hope Sertularia pumila, Linn. Mr. Hope says he has found this at all seasons near Harwich — operculata, Linn. Found by Mr. Hope near Harwich 12
