812 PROCEEDINGS OF THE ACADEMY OF [DeC, 



In this Hemi'phcedusa of the group of C. aulacophora the phcse and 

 lamellae penetrate very deeply — across "the ventral side — and the 

 lunella stands in a ventral position, above the coliimellar margin of the 

 peristome. In C. aulacophora and C. pigra the lunella is lateral, but 

 of the same shape. C. ventriluna is very closely related to C. cary- 

 ostoma and C. c. jayi, which have the armature similarly deep-seated ; 

 but neither of these forms has a perfect lunella uniting the two palatal 

 plicae. 



The clausilium is not thickened distally as in Tyrannophcedusa, but 

 otherwise C. ventriluna has much in common with C. (Tyr.) aurantiaca. 



Other specimens from Tsushima, Awa (Shikoku), are smaller than 

 those from Yasuda-mura, and the superior lamella is either separated 

 from the spiral lamella or but weakly connected therewith. The prin- 

 cipal plica is a little shorter inside. In some of the specimens the sub- 

 columellar lamella emerges to the lip-edge, and is bounded by furrows. 

 In others it is immersed or very feebly and slightly emerges. These 

 shells are No. 1,187 of Mr. Hirase's collection. 



Clausilia ikiensis n. sp. PI. LV, figs. 45, 46, 50, 51. 



Shell small, fusiform, dark or pale reddish-brown, somewhat shining, 

 weakly striatulate, the last whorl becoming densely and finely striate 

 on the back. Spire decidedly attenuate above. Wliorls 9^, convex, 

 the last somewhat flattened peripherally. Aperture rhombic-ovate, 

 somewhat oblique, the peristome continuous, reflexed and somewhat 

 thickened within; the parietal margin well raised, straight or a little 

 emarginate over the superior lamella. Superior lamella slightly 

 oblique, compressed, marginal, continuous with the spiral lamella, 

 which extends inward scarcely to the middle of the ventral side. 

 Inferior lamella deeply receding, straightly ascending within the back, 

 not penetrating quite so deeply as the spiral lamella. Subcolumellar 

 lamella very weakly emerging. Principal plica not long, dorsal and 

 lateral. Upper palatal .plica short, united in the middle to the oblique ,• 

 narrow lunella, which curves inward below. Below the lower end of 

 the lunella there is a short, straight lower palatal plica. 



Length 12, diam. 3 mm. 



Length 11.5, diam. 2.8 mm. 



The clausilium (PI. LV, figs. 50, 51) is parallel-sided, rounded dis- 

 tally, and deeply excised on the columellar side of the filament. It is 

 decidedly arcuate. 



Mush5zumura, Iki. Types No. 86,063, A. N. S. P., from No. 1,088 

 of Mr. Hirase's collection. 



This Hemiphcedusa is structurally similar to species of the group of 



