1902.] NATURAL SCIENCES OF PHILADELPHIA. 373 



oblique and a little thickened; columellar side excised near the 

 filament. 



Yaku-shima, Osumi. Types No. 82,958, A. N. S. P., from No. 

 894 of Mr. Hirase's collection. 



Very distinct from any known Japanese or Riukiuan species. 

 The strength and coarseness of the sculpture is remarkable in so 

 small a shell. The lamellse and plicae penetrate less deeply than 

 usual. 



One specimen (PI. XIX, fig. 49) is larger and more obese than 

 the others of the type lot, but it agrees in other characters. 



The ribs are shown a little too much spaced on the last whorl of 

 fig. 48. 



Group of C. aulacopoma. 



Shell similar to that of the group of 0. awajiensis, except that a 

 nodule-like lower palatal plica is developed inward from the termi- 

 nation of the lunella. Clausilium strongly curved, channeled on 

 the outside at the apex. 



The single species at present composing this group is strongly 

 individualized by the peculiar modification of the clausilium. 



Clausilia aulacopoma Pilsbry. PI. XVII, figs. 12, 13, 14, 15, 16. 



These Proceedings for 1901, LIU, p. 656, footnote No. 11 (March 1, 

 1902). 



Shell fusiform, strongly attenuated above, brown, the surface 

 lustreless, finely and weakly striate, more strongly so on the back 

 of the last whorl. Whorls about 9-J-, convex, the apex small. 

 Aperture trapezoidal-ovate, a little oblique. Peristome reflexed 

 and thickened. Sinulus distinct and slightly retracted. Superior 

 lamella marginal, small and low, continuous with the spiral lamella, 

 which penetrates to the middle of the ventral side. Inferior 

 lamella deeply receding, straightly ascending within the last whorl, 

 distinctly thickened and a little sinuous near its lower end, a little 

 shorter within than the spiral lamella. Subcolumellar lamella 

 emerging to the lip-edge, though sometimes but weakly, and 

 bounded by grooves. Principal plica extending from the dorsal 

 nearly to the ventral side. Upper palatal plica short, united in the 

 middle to the strong oblique, latero-dorsal lunella, which is straight 

 above and curves inward below, its inner end being contiguous to 

 a strong short, nodule-like lower palatal plica. 



