1902.] NATURAL SCIENCES OF PHILADELPHIA. 519 



ish or greenish. There is no evidence of coarser strialion on the 

 back of the last whorl. 



The unusual thickness of the early whorls separates this form 

 from C. suhulina var. leucopeas and C. seHcina var. rhopalia. 

 C. heteroptyx is a much larger species with different palatal arma- 

 ture. The unusual thinness of the shell also distinguishes C. kuro- 

 zuenms, though this may be partly due to the worn condition of the 

 type specimens. 



Section STEREOPHiEDUSA Bttg. 

 Clausilia plagioptyx n. sp. PI. XXVII, figs. 8, 9. 10. 



Shell solid, fusiform, much attenuated above, the first two whorls 

 being small and of about equal diameter, giving the shell an awl- 

 like shape ; light-brown, the first whorls whitish. Somewhat glossy, 

 closely and finely striate, the strije perceptibly more widely spaced 

 on the last whorl. Whorls 9|, moderately convex, the last one 

 somewhat compressed. Aperture rhombic-piriform ; peristome 

 reflexed, thickened, white or jiale- brownish. Superior lamella 

 marginal, continuous with the spiral lamella, which penetrates to 

 a point above the superior lamella. Inferior lamella approaching 

 the superior, and equally long inside. Subcolumellar lamella 

 emerging to the lip-edge. Principal plica lateral, about a half 

 whorl long. Palatal plicse four, the upper longest, converging 

 inward toward the principal plica, or parallel with it ; the second 

 and third either subequal and short, parallel to the upper plica, or 

 the third plica may be reduced to an elevated point. Loiver plica 

 very obliquely descending, standing almost as a short, oblique 

 and straight lunella. 



Length 17, diam. 4 mm. 



Goto, Hizen. Types No. 82,644, A. N. S. P., from No. 817 

 of Mr. Hirase's collection. 



This species is based upon specimens which I listed under 

 C. brevior as from " Goto, XJzen.'" Upon opening specimens I 

 find that the palatal structure differs iu a very characteristic 

 manner. 



The exterior is almost exactly like C. brevior, but it is a less 

 swollen shell than most specimens of that species ; but while 

 C. brevior has a well-developed lower palatal plica about parallel 



1 These Proceedings for 1901, p. 653. 



