564 



PROCEEDINGS OF THE ACADEMY OF 



[Dec. 



Group of Clausilia aculus. 

 Clausilia tripleuroptyx n. sp. PI. XXXI, figs. 1, 2. 



The shell is fusiform, the lower three whorls rather large, those 

 above tapering to the attenuate summit; brown or chocolate colored, 

 moderately glossy, the last 3 or 4 whorls sharply, finely striate, the 



Fig. 3. — Clausilia tripleuroptyx, a, h, two views of clausilium ; c, last whorl and 

 aperture; d, e, diagrams of palatal armature of two individuals. 



striae a little coarser on the back of the last whorl. Whorls about 9, 

 convex, the last flattened laterally, tapering downward. The aper- 

 ture is squarish-ovate; peristome pale, well reflexed, continuous. 

 Superior lamella marginal, of moderate size, compressed, continuous 

 with the spiral lamella, penetrating to the middle of the ventral side. 

 The inferior lamella approaches the superior, ascends in a broad 

 spiral curve, and penetrates as deeply as the spiral lamella. The 

 subcolumellar lamella is deeply immersed. The principal plica is 

 rather short, lateral. There are usually three palatal pHcse below 

 the principal, the upper well developed, a very short plica below it. 

 There is no lunella, but a lower palatal plica about as long as the upper 

 is present (fig. 3d). 



Length 14.5, diam. 3.4 mm. 

 " 13.8, " 3.0 " 



The clausilium is strongly curved, oblique and subangular at the 

 apex, a little excised at the columellar side of the filament (fig. 3a, 6). 



Kuroshima, Satsuma. Types No. 95710 A. N. S. P., from No. 1589 

 of Mr. Hirase's collection. 



This species is related to C. digonoptyx Bttg., but diffei's by its palatal 

 plicae and the more curved, differently shaped clausilium. It differs 

 from C. subaculus by the better developed superior lamella and the 

 different palatal armature. C. aculus Bens, of China and Korea is 



