ART. 6 A NEW WEST INDIAN MOLLXJSK FAUNULA BARTSCH 5 



tip consists of not quite a single turn, which is well rounded, smooth, 

 and white. The succeeding turns are a little less strongly roi'ndevi, 

 feebly shouldered at the summit, and marked by fine retractively 

 slanting incremental lines and slender spiral threads. These threads 

 are almost equal in strength and spacing. Eleven of them are pres- 

 ent on all the whorls between the summit and suture. They increase 

 in strength as the whorls increase in size. In addition to these 

 raised threads, finer spiral striations are present in the interstices 

 between them. Periphery well rounded. Base inflated, well 

 rounded, marked by a continuation of the incremental lines and low 

 flattened spiral threads, equaling those on the spire in width, but less 

 elevated. Aperture semioval; outer lip slightly expanded, par- 

 ticularly so at the junction of the basal and outer lip and slightly 

 reflected. Columella short, curved; inner lip reflected over the last 

 whorl as a white callus, which extends up on the parietal wall. 

 Operculum unknown. 



Type.—ThQ type, U.S.N.M. No. 403922, has 6.5 whorls and meas- 

 ures: Length, 16.2 mm; greater diameter, 16.2 mm; lesser diameter, 

 12.9 mm. 



Remarks. — U.S.N.M. No. 403884 contains 18 additional specimens 

 from the type locality. 



This species belongs in the group of Eutrochatella globosa Gray 

 and E. opima Shuttleworth. It differs from E. glohosa in being 

 much more globose, and from E. opima in being much larger and 

 being even still more globose. The sculpture in the present species, 

 moreover, is much finer in every way. 



CERATODISCUS BEATENSIS, new species 



Prji.TE 2, Figures 1, 2, 3 



Shell very minute, discoid, pale horn-colored, upper surface of the 

 whorls forming a concave disk. The nucleus consists of a single, 

 rather large, smooth, well-rounded whorl, which does not project 

 above the rest of the turns. The postnuclear whorls are marked by 

 rather rough incremental lines, which are irregular both in size and 

 spacing, and by slender, wavy spiral threads, of which five are ap- 

 parent on the first postnuclear whorl. The last whorl is solute for 

 about one-tenth of a turn and in cross section is broadly semioval, 

 the columellar side being more or less straight. This whorl is also 

 marked by coarse incremental lines and spiral threads both on 

 the upper surface and the curved peripheral edge, and the well- 

 rounded basal portion. The base is decidedly concave with an open 

 funnel-shaped umbilicus. Aperture semioval; the peristome very 

 slightly expanded and very slightly reflected at the edge. 



