﻿ADDENDUM. 



181 



material difference between it and some of the recent forms of pespelicani. A. MacAndreee 

 is probably only a variety. Chenopus deciscens, Phil., I do not know, but this is described 

 as " ultimo quadricarinato carinis nodulosis," while my shell has only three keels or ridges. 



Cerithium (Triforis) perversum ? Linne, var. Belli. Addendum Plate, fig. 17. 

 Locality. Cor. Crag, Sutton. 



The above figure represents a small specimen sent to me by Mr. Robert Bell without 

 a name. 



The two forms or varieties called C. perversum and C. adversum (the latter of which 

 is rather more slender than the other) are both found in the Cor. Crag at Sutton ; but I 

 have seen nothing so cylindrical as the present specimen. The recent shell, to which I 

 have doubtfully referred it, is described by Mr. Jeffreys as variable, the volutions having 

 three and sometimes four bands (' Brit. Conch.,' vol. iv, p. 261). 



As our present shell has four unequal ridges (the lowest one very small, and the next 

 one to it large and nodulous) I have not ventured to consider it as a distinct species on 

 the strength of a solitary specimen, though, should more specimens occur, the question 

 of its specific separation might with more reason be entertained. 



Cerithiopsis tubercularis, Mont. Crag Moll., p. 70, Tab. VIII, fig. 5, Supplement, 



p. 52. 



Since the first part of this £ Supplement ' was issued Mr. Jeffreys kindly sent me for 

 examination his British recent specimens, from which he formed two distinct species, 

 under the names of C. Barleei and C.pulchella (' Brit. Conch.,' vol. v, PI. 81, figs. 2 and 3). 

 It does not appear to me that these shells present sufficient differences from tubercularis 

 to entitle them to specific isolation, but they have all their exact representations among 

 the Cor. Crag specimens. The principal differences appear to be a basal ridge or 

 prominent spiral line which is present in some of my Crag specimens. Under these 

 circumstances I have still retained them under the same specific name of tubercularis. 

 Var. subulata, of ' Crag Moll.,' Tab. VIII, fig. 5 b, represents C. Barleei, and var. nana 

 fig. 5 c represents C. pidchella, the convexity in the volution of this latter being 

 probably caused by its abbreviated spire. 



I have adopted the above generic name in deference to the malacologists, who say 

 that there is a great difference in the animal from that of Cerithium, and this is 

 also strengthened (it is said) by the present genus possessing a longer canal. 



