206 



DESCRIPTION OF A NEW SUBGENUS AND SPECIES OF ALYCjEUS 

 FROM KE-LAN-TAN. 



By H. B. Preston, F.Z.S. 



Read 9th November, 1906. 



Among a number of shells from Ke-lan-tan whicli recently came 

 into my possession there was included a species which I at first 

 thought belonged to the genus Ali/cceus, but, upon careful examination 

 of the operculum, I found that it bore characters totally different from 

 those of the hitherto described typical species of that genus, and which 

 appeared to make it quite worthy of subgeneric rank. I therefore 

 now propose the new subgeneric name Pincerna for the shell in 

 question, and venture to describe it as below. 



Pincerna, nov. subgen. 

 Shell Alycaeiforra ; operculum horny, convex below, concave above, 

 bearing in the centre of the upper surface a hollow protuberance in 

 the form of a circular cup, the margin of which is slightly reflexed 

 outwards. 



Pincerna lieatula, n.sp. 

 Shell conical, pale yellowish horn colour; whorls 4^, convex; the 

 first whorl and a half smooth, the remaining whorls sculptured with 

 fine spiral lirae, and somewhat coarse transverse ribs which are much 

 more numerous and closely set on the body-whorl ; last whorl 

 constricted about two and a half millimeters from the aperture and 

 destitute of transverse ribs in the constricted area ; suture deeply 

 impressed ; aperture circular ; peristome continuous, double, and 



reflexed outwards ; umbilicus narrow and deep, partly concealed by the 

 reflexed peristome, which, owing to a notch or depression at this point, 

 is expanded outwards and downwards ; operculum horny, convex 

 below, concave above, bearing in the centre of the upper surface 

 a hollow cup-shaped protuberance, the margin of which is slightly 

 reflexed outwards. Alt. 5-5 mm. ; diam. maj. 4-5 mm. ; aperture, 

 diam. 2 mm. 



Hab. — Ke-lan-tan. 



