122 Gontributions to Lidian Malacology. [No. 2, 



the Nilgiris. As all the specimens found were dead shells and ifc 

 seemed most desirable to obtain living specimens in order to deter- 

 mine satisfactorily the nature of the species from an inspection oí' 

 the animal, we have hitherto abstained from publishing a description 

 vvhich must of necessity be imperfect, in the hope, either that one of 

 ourselves might revisit the bilis and procure a supply of livmg speci- 

 mens, or that someof our fiiends conchologically inclined, might aid us 

 in the matter. Wehave, we regret to say, been disappointed in these 

 expectations, and we therefore publish the description and figure of the 

 shell, hoping that publicity may lead others to the search, and we 

 leave the question of the nature of the animal and the existence of 

 an operculum to be settled at some future period. 



To the kind aid of Capt. Mitchell of Madras we are indebted for 

 the accompanying figures, drawn with the aid of the camera lucida, 

 and magnified about 30 diameters. The specimen from which the 

 drawings are taken is in excellent preservation and shews very clearly 

 not only the costulation, which bears a great resemblance to that of 

 Diplommalina and Alycceus, but also a regular scalariform decussation 

 of the interstitial spaces which is represented on an enlarged scale in 

 figure 5. This costulation and more especially the Alycceus-Wke 

 strangulation and inflation of the last whorl point to the probability 

 of the present being an operculate genus, and the round whorls and 

 continuous and duplícate peristome lead to the same conclusión. No 

 trace of a tube is perceptible on any part of the shell. 



From these characters we should infer that Opistliostoma liolds an 

 intermedíate place between AIijccbus and Diplommatina, resembling 

 the former in the strangulation and distortion of the last whorl, 

 the latter in the pupiform shnpe and in the rise of the last whorl 

 upon the penultimate, and both in the duplication of the peristome, 

 and in the regular costulate ornamentation : but the peculiar distor- 

 tion of the apicial whorls and the hyperstomoid flexure of the last 

 whorl are characters not hitherto found in any operculate genus, and 

 having their analogues in Streptaocis and JBoysia among inoperculate 

 shells. Seeing, however, the great variation of spiral form that 

 obtains in the different Cyclostomaceous genera, no great weight can, 

 we think, be attached to spiral peculiarities when opposed to the 

 evidence of the characters above enumerated which connect Opisthos- 



