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,]J\xin. 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 



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