GASTEROPODA. 51 



they give to the complete shell being very different. Mr. A. Bell gives C. reticulatum from 

 the Red Crag of Walton ('Ann. and Mag./ September, 1870), but I have not seen the 

 specimen, and imagine that it may probably be the variculosum of that locality. 



Cerithium tricinctum, Broc. Crag Moll., p. 69, Tab. VIII, fig. 1, a and b. Supple- 

 ment, Tab. Ill, fig. 19. 



Locality. Cor. Crag, Sutton, and near Orford. Red Crag passim. Fluvio-marine 

 Crag, Bramerton. Chillesford Bed, Bramerton and Horstead. Middle Glacial, Hopton. 



The above figure, 19, was made from a fragment of this species, which I had obtained 

 from the Cor. Crag of Sutton, and it was inserted in order to justify its admission among 

 the shells of that formation. Since the plate was engraved, however, I am glad to say 

 that I have obtained three other specimens from the Coralline Crag of the neighbourhood 

 of Orford (Gomer pit), one of which is nearly perfect, and would be exactly represented 

 by the old figure la, of Tab. VIII, of the * Crag Mollusca.' This species is common in 

 the Red Crag and in the Fluvio-marine Crag at Bramerton, as well as in the Chillesford 

 Bed at that place. It occurs also, but rarely, in what I consider to be its Fluvio- 

 marine representative — the Crag of Horstead, but I have not seen it from the other 

 localities of that bed. I have not met with it from the Lower Glacial sands ; but one 

 specimen, which fig. 19, of Tab. Ill, would well represent, has occurred in the Middle 

 Glacial sand of Hopton. I do not know it living. 



Mr, Charlesworth has also given me'a specimen, too mutilated for figuring of a species 

 of this genus, but the characters are not sufficiently distinct for specific determination. 

 In this the volutions are more close and numerous than those of C. tricinctum, as were 

 remarked to me by Mr. Charlesworth ; it is, I believe, distinct. He obtained it from the 

 nodule bed at Waldringfield, and is probably a derivative in the Red Crag. 



Fig. 21, of Tab. Ill, of this ' Supplement,' represents an imperfect specimen obtained by 

 myself from the Post Glacial Freshwater Deposit at Grays. Mutilated specimens of Melania 

 inauinata, and another species of Melania, have got into this deposit at Grays, from the 

 Eocene Woolwich sands, and the specimen produced may therefore be of similar origin, as 

 it resembles Cerithium (JPotamides) intermedium, of Sowerby, from those sands (' Min. Cor.,' 

 Tab. CXLVII, fig. 3.) I was induced to figure its form, from the difference between the 

 character and composition of this specimen, and that of these older tertiary derivatives; 

 the Melania being strong shells, much abraded, while the specimen figured was so fragile 

 that it fell to pieces, leaving only the fragment figured, and disclosed that it was 6 lied 

 with the material of the Grays Deposit, and not that of the Eocene one, which at first 

 induced me to suppose that it might have been a living denizen of the waters of the 

 Grays deposit. I have figured it simply as a shell found in the Grays Bed, without 

 venturing to express a positive opinion about it. 



