GASTEROPODA. 23 



CERITHIUM VARICULOSUM, Nyst. Crag Moll., vol. i, p. 69, Tab. VIII, fig. 3 ; 2nd Sup., 



Tab. II, fig. 15. 



Locality. Red Crag, Walton Naze. 



The figure given of this shell in the ' Crag Moll/ does not quite correctly represent the 

 fossil found at Walton Naze, which in Prestwich's list is referred to Cerithium reticulatum, 

 but which I believe is specifically distinct ; the volutions of my fossil are more convex, and 

 are not only destitute of thickened varices, but have a different ornamentation from the 

 recent shell. I have now figured a fragment found by myself at Walton Naze ; and this 

 has decidedly convex volutions, with three spiral and nodulous ridges, and a small one 

 at the base ; moreover, these spiral ridges are not equally distributed over the whorls, 

 there being a wider space between the upper one and the suture, than there is between 

 the others. In C. reticulatum the volutions are nearly flat and have four equidistant 

 nodulous striae. I have therefore retained the shell under the name originally given. 



CERITHIUM GREENII? Adams. 2nd Sp., Tab. IV, fig. 16. 



CERITHIUM GREENII, Adams. Boat. Journ. Nat. Hist., vol. xi, p. 287, pi. iv, fig. 12. 



Locality. Chillesford Bed, Bramerton. 



Two small but very perfect specimens of some species of the genus Cerithium have 

 been sent to me by Mr. Reeve with the locality of "Upper bed at Bramerton." I have 

 a difficulty in referring them to anything previously described, and have therefore given 

 them provisionally the above name. The shell to which they present the nearest approach 

 is Cerithium Greenii, C. B. Adams, figured and described by Gould (' Invert. Mass.,' p. 279, 

 fig. 184), but I have not the recent shell to compare with it. In 'Brit. Conch./ vol. iv, 

 p. 267, it is said that C. Greenii is the same as Cerithiopsis tubercularis, but my shell 

 does not correspond with anything that I have seen of this very variable species. It does 

 not seem possible that it can be the young of C. tricinctum, though it does not exceed 

 in length -ft\\s of an inch, for it has seven volutions, which is repugnant to its being the 

 young of any species. The base of our very perfect specimens is quite free from striae or 

 markings of any kind, and the volutions, which have three nodules, are separated by a 

 deep suture, the two forming the apex being smooth. If the shell should prove distinct 

 from Greenii the name Reevii might be assigned to it, as the specimen was found and 

 sent to me by Mr. Reeve, of the Norwich Museum. 



