510 PROCEEDINGS OF THE ACADEMY OF [DcC, 



Section SELENOPTYX nov. 



Shell with the oblique ventral lunella and the upper palatal plica 

 united into a continuous crescentic barrier, the convex side of the 

 crescent inward and upward; otherwise like Hemizaptyx. Clausilium 

 excised on the colurnellar side at the filament. Palatal border 

 reflexed, the lower half more or less excised. Type C. noviluna. 



This group is unlike any other in palatal armature, the inner end of 

 the upper palatal plica passing directly into the oblique lunella, forming 

 a crescent which may be somewhat angular in the middle. This is 

 ventrally or latero-ventrally situated, and except in old, opaque shells 

 is visible through the front of the shell. The inferior lamella is remote 

 from the superior, not visible in a front view, vertical within, with a 

 bend to the left in the middle. The clausilium is peculiar. 

 Clausilia noviluna n. sp. PI. XXXIV, figs. 34-39. 



Shell fusiform, attenuate above. Whorls about lOJ, the upper ones 

 convex, the last flattened laterally. Surface glossy, brown, densely 

 and very finely striate throughout, the striation not coarser on the last 

 whorl. Aperature rhombic-ovate, the peristome expanded, thick. 

 The superior lamella is slightly oblique, thin and rather high, marginal, 

 continuous with the spiral lamella which is very low within the back, 

 but high ventrally, penetrating past the aperture. The inferior 

 lamella recedes deeply, is flattened and ascends vertically within the 

 back, then bends abruptly to the left, and finally ascends again. It 

 is not continued parallel to the spiral lamella. The subcolumellar 

 lamella emerges. It is weak throughout. The principal plica is more 

 than a half whorl long, dorsal and lateral extending nearly to the 

 aperture. The upper palatal plica is of moderate length, inwardly 

 continuous with the obliquely descending lunella, which is latero- 

 ventral in position. There are no accessory lamellae or plica?. 



Length 10.7, diam. 2.8 mm. 

 8.5 " 2.3 " 



The clausilium (PI. XXXIV, figs. 34, 35, 36) is abruptly excised on 

 the colurnellar side of the filament. In the middle of the palatal 

 margin there is a backwardly projecting point or angle of the recurved 

 margin, below which the edge is notched and irregular. 



Iheya-jima, Ryukyu. Types No. 90,046, A. N. S. P., from No. 

 1,356 of Mr. Hirase's collection. 



This curious little snail is related to the following species, having the 

 same kind of palatal plica and lunella, completely united into a single 

 curved barrier {noviluna, new moon, in allusion to the narrow, curved 

 lunella). 



