64 Zoological Society : — 



It is to be observed that in Area tortuosa and A. semitorta the 

 hinge-line is always straight, and it is only the basal line which is 

 bent to one side, the valves being slightly unequal, and in fact the 

 shell is not distorted ; while in the Hyria under consideration the 

 upper edge of the shell is bent as well as the lower one, and the 

 shell is truly altered in form by some external circumstance. 



The shells appear as if they had been softened and suddenly 

 twisted on one side. It has been suggested that this change in the 

 form may be produced by the position which the shell occupies in 

 the mud or under the stones near which it lives ; but it is to be 

 observed that Uniones generally live sunk in the mud, and not lying on 

 one side, and that, like shells which live in an erect position, they have 

 equal valves, while those that live lying on their side almost always 

 have unequal ones ; and if the form depended on this circumstance, 

 as the animal must sometimes move and must be sometimes turned 

 over, we ought to find some specimens with the flexure partly on 

 one side and partly on the other, but no such specimens have 

 occurred to me. 



I am inclined to believe that it arises from some peculiar predi- 

 lection of the animal itself, by which it probably more easily obtains 

 its food in the peculiar situation in which it resides. 



These shells were sent to England from China by one of Mr. For- 

 tune's collectors. They were accompanied by some specimens of 

 reptiles and insects, on which the Chinese collectors had been exer- 

 cising their ingenuity in hopes of adding to their value. Thus there 

 was a stuffed specimen of a Night Lizard (Geeko Reevesii) which 

 had a square tuft of hair from some mammal stuck on the back of 

 its neck. 



A Snake, which had the claw of a mammal surrounded with fur 

 inserted on each side of its neck just behind the head, so as to make 

 it appear as if it had rudimentary feet armed with large claws. 



Several of the Coleopterous insects, especially the larger Ceram- 

 byces, were painted, so as to give them quite a different appearance 

 from the usual and natural colour of the species. 



I may add that the work was so coarsely executed as to be dis- 

 covered on the most cursory examination of the specimens, and could 

 only have been intended to deceive the most ignorant collectors. 



Observations on the Genus Nerita and its Operculum. 

 By Dr. J. E. Gray, F.R.S., V.P.Z.S., etc. 



The distinction of the species of this genus is rather difficult ; 

 therefore whatever assists in dividing the species into smaller groups 

 is of use, as limiting the number of species between which any doubt 

 can be entertained. 



Considerable confidence has therefore been placed in the form of 

 the surface of the inner lip, which in some species is smooth, in 

 others tubercular or ridged, or both ridged and tubercular; but 

 in examining a large series of specimens from the same locality, 

 though the character is generally permanent, the tubercles or ridges 



