414 PROCEEDINGS OF THE ACADEMY OF 



Hemiphcedusa, but unlike that group, an upper palatal plica is 

 developed. The clausilium is very peculiar. 



Clausilia nesiothauma n. sp. PI. xxil, figs. 19, 20, 21. 



Shell large, fusiform, rather obese below, moderately tapering 

 above, fleshy -whitish, the surface lustreless and (where not over- 

 grown with algse or worn smooth) sculptured with moderately 

 coarse, somewhat waved rib-strise, branching or with intercalated 

 strise on the upper half of the last whorl. Apex small, the first 

 whorl rapidly enlarging, sometimes self-amputated and plugged. 

 Whorls 10, the last tapering below, having a broadly rounded basal 

 crest running to the lower angle of the aperture. Aperture verti- 

 cal, semicircular in general contour, obtusely angular at the sinulus 

 and at the foot of the columella; the inner margin being straight- 

 ened, the outer rounded. Peristome white, the outer and basal 

 margins flaring, broadly reflexed, the inner margin sloping, emar- 

 ginate at the termination of the superior lamella, arcuate along 

 the interlamellar space, then straightened. Superior lamella 

 strong, slightly oblique, marginal, continuous with the spiral 

 lamella. Inferior lamella very strong, calloused and thick, forming 

 a squarish columellar fold, abruptly lower or sometimes bifid where 

 it extends upon the peristome. Subcolumellar lamella emerging, 

 very strong and prominent, extending to the lip-edge. Principal 

 plica about one-third of a whorl long, lateral in position. Lunella 

 arcuate, its upper end curving well inward (being completely united 

 with, and curving into, a short upper palatal plica); below, the 

 lunella becomes strong and high, and joins the middle of an ex- 

 tremely strong, long, arched lower palatal fold, the summit of which 

 curves downward and almost meets a broad, erect plate which at 

 this point rises from the subcolumellar lamella. The lower end of 

 the lower palatal plica is visible from the aperture, in a front or 

 slightly oblique view. The inferior lamella is continued inward as 

 a strongly spiral erect plate, rather distant from the spiral lamella 

 on the dorsal side, but approaching it and becoming rather abruptly 

 lower ventrally, both penetrating to beyond the middle of the ven- 

 tral side. The subcolumellar lamella inward from the expansion 

 toward the lower palatal plica, is slightly sigmoid, and not parallel 

 inside with the inferior lamella. 



Clausilium (figs. 15, 16) rather broad in the middle, slightly 

 tapering toward each end, the lower end abruptly truncate, emar- 



