568 PROCEEDINGS OF THE ACADEMY OF [DcC, 



Shells from Suwanosejima are much smaller: 



Length 12, diam. 2.9 to 3 mm.; whorls 8^ (pi. XXXI, fig. 6). 



Clausilia nishinosMmana n. sp. PI. XXXI, fig. 7. 



A Stereophcedusa of the group of C. hrevior. The shell is fusiform, 

 tapering from the penultimate whorl, considerably attenuated near 

 the apex; dull dark brown; rather finely and 

 sharply striate except the earher whorls, which 

 are worn. Whorls 11^, moderately convex, the 

 second, third and fourth of about equal diameter, 

 the last compressed and tapering downward. Ap- 

 erture ovate, the sinulus a little retracted. Peris- 

 tome brown tinted, rather broadly reflexed, 

 recurved at the edge, thick. Superior lamella a 

 little oblique, marginal, continuous with the 

 spiral lamella, which is high and lamellar in the 

 middle, low toward both ends, and penetrates 

 inward to a point above the outer lip. The inferior 

 lamella forms a rather strong fold in the throat, and ascends in a broad 

 spiral curve in the back, where it is very wide. It penetrates as deeply 

 as the spiral lamella. The subcolumellar lamella emerges to the 

 lip edge. The principal plica is weak, short and lateral. There are 

 short upper and lower palatal plicse, but no lunella (fig. 4). 

 Length 18, diam. 3.9 mm. 



The clausilium is strongly curved, somewhat angular at the apex, 

 a little excised on the columellar side of the filament. It is similar to 

 the clausilium of C. hrevior} 



Nishinoshima, Oki. Types No. 95689 A. N. S. P., from No. 1576 

 of Mr. Hirase's collection. 



This species is closely related to C. hrevior, differing in the following 

 respects : There are but two palatal plicse below the principal one, 

 which is much shorter than in C. hrevior; the spire tapers for a longer 

 distance, and it is composed of more whorls. 



Some individuals lose the early whorls, closing the breach with a 

 convex plug, as in some Urocoptids. The number of whorls retained 

 may be reduced to six. Among some hundreds of C. hrevior seen from 

 six localities, none were similarly truncate. It is a rather unusual 

 condition in Japanese Clausiliidce. 



« See Proc. A. N. S. Phila., 1901, pi. 38, figs. 52, 53. 



