BY H. LEIGHTON KESTEVEN. 



633 



of it in this manner was apparently in deference to the opinion 

 of E. A. Smith, who, in dealing with the type, had said : — "The 

 interior of the aperture is not pearly as in the Trochidse; and yet 

 the operculum truly appertains to that family, being concentric 

 and multispiral; and although, therefore, differing from that of 

 Eisella, the shell itself appears to suggest the joropriety of its 

 being located with that genus rather than with the Trochidse" 

 (19). Disregarding the peculiarly contradictory phrasing of this 

 statement, the conclusion seems to be a good deal at fault. The 

 resemblance of the shell to Risella is very slight, and, as stated, 

 the opercula — characters of infinitely more importance — are of 

 two distinct types. The dentition (Text fig. 1) resembles that of 



Fig. 1 — Operculum and dentition of Peasiella tantillus, Gould. 



Littorina more nearly than any other; but that of Modulus, with 

 which I would place Peasiella as a full and valid genus, is of the 

 same type. The operculum also favours this allocation. 



Hedley (8) has drawn attention to the fact that Echinella 

 gaidii, Montrouzier (H), is a synonym of Trochus conoidalis, 

 Pease (15). Montrouzier describes the operculum as normal — 

 that is, corneous and multispiral, since such is the operculum of 

 the genus to which he referred it. The species is, therefore, a 

 Peasiella; but whether the other species which have been placed 

 here (-u^'c^e Tr^^on, 25, pp- 263-264) belong to this or distinct genera 



