1902.] NATURAL SCIENCES OF PHILADELPHIA. 521 



Surface glossy, densely striate, more or less worn above. Whorls 

 llj to 12, somewhat convex, the penultimate widest, convex, the 

 last whorl flattened laterally, convex below. Aperture piriform, 

 whitish within. Peristome thickened within and reflexed, white, 

 very shortly free, and usually a trifle notched over the superior 

 lamella. Superior lamella oblique and submarginal, continuous 

 with the spiral lamella, which penetrates to the middle of the ven- 

 tral side. Inferior lamella forming a conspicuous, subhorizontal 

 fold in the aperture, approaching the superior lamella, ascending 

 within with a broad spiral trend, and penetrating deeper than the 

 spiral lamella. Subcolumellar lamella emerging but not reaching 

 the lip-edge. Principal plica short, arising about the middle of the 

 dorsal side and extending past the middle of the right side, 

 scarcely or not deeper than the inner end of the upper palatal plica. 

 Palatal plicse two or one, the upper plica strong, converging inward 

 to the principal plica, the lower plica xveah and low or ivantiiig. 



Length 26, diam. 5.8 mm. 



Length 25, diam. 5 mm. 



Clausilium (PI. XXVII, figs. 15, 16) broad below the middle, 

 the distal fourth abruptly curved, nearly at a right angle with the 

 middle portion, tapering to a rather acute, thickened apex, the 

 palatal margin straight near the apex, and a trifle excised close to 

 it. Above, it tapers to the filament, and is not excised or emar- 

 giuate. 



Mikuriya, Suruga (Hirase; types of C. j. surugce and C. e. 

 hrachyptychia) . Hakone, Sagami (Hungerford; types of 

 C. oostoma). 



This species has been the subject of several notices by Dr. 0. 

 von Mollendorff and myself, but it has not hitherto been ade- 

 quately illustrated. Figures are now supplied for comparison with 

 the related forms dactylopoma and goniapoma. The above descrip- 

 tion and the figures are from the types of C. jajjonica var. surugw^ 

 which is undoubtedly specifically identical with C. oostoma. 

 Clausilia oostoma var. dactylopoma "ov. PL XXVH, figs. 19,20. 



Specimens from Kashio, Awaji, are a little shorter, witli 1 1 to 

 11^ whorls, and have the lower palatal plica well developed. Tlioy 

 have the comparatively fine, even striation of the form from Miku- 

 riya, Suruga. 



Length 22-25.5, diam. 5.2 nun. 



