332 PROCEEDINGS OP THE NATIONAL MUSEUM. vol.40. 



ribs which are as strong as the spiral cords and render the junctions 

 with these nodulose. Of these ribs 16 occur upon the first to fifth, 

 18 upon the sixth, 20 upon the seventh, and 22 upon the penultimate 

 turn. The spaces inclosed between the axial ribs and spiral cords 

 appear as strongly impressed, rounded pits. The tubercles are 

 slightly truncated posteriorly, sloping gently anteriorly. Periphery 

 of the last whorl marked by a channel like those occurring between 

 the spiral cords on the spire and like them crossed by the continua- 

 tions of the axial ribs. Base rather long, well rounded, free from 

 sculpture excepting very fine, incremental lines. Aperture regularly 

 ovoid, strongly channeled anteriorly; posterior angle obtuse, outer 

 lip thin, rendered wavy by the external sculpture; columella stout, 

 decidedly curved and somewhat twisted, projecting considerably 

 beyond the anterior margin of the outer lip. 



The type and seven specimens (Cat. No. 195194, U.S.N.M.) come 

 from the Lower Pleistocene (Lower San Pedro Series), Deadmans 

 Island, California. The type has twelve whorls and measures: 

 Length 6 mm., diameter 1.6 mm. 



CERITHIOPSIS (CERITHIOPSIS) OXYS, new species. 



Plate 36, fig. 2. 



Shell minute, elongate-conic, dark brown. Nuclear whorls almost 

 four, forming a slender, elongate-conic spire, having the whorls well 

 rounded. Post-nuclear whorls well rounded, separated by a strongly 

 channeled suture, marked b}^ three equally strong, spiral cords, the 

 first of winch is at the summit, the third slightly above the periphery, 

 while the second is median between these two. In addition to the 

 spiral cords, the whorls are marked by vertical, axial ribs, almost as 

 strong as the spiral cords. Of these ribs, 16 occur upon the first, 

 20 upon the second, 18 upon the third to fifth, and 24 upon the 

 penultimate turn. The junctions of the axial ribs and spiral cords 

 form strong tubercles of which those of the posterior cord are rounded 

 while the other two are truncated posteriorly and slope gently ante- 

 riorly, while the spaces inclosed between the spiral cords and axial 

 ribs are strongly impressed, rounded pits. Periphery of the last 

 whorl marked by a strong cord winch is feebly nodulose and separated 

 from the tuberculate keel posterior to it by a channel as wide as those 

 occurring on the spire; tins channel is marked by the continuations 

 of the axial ribs. Base moderately long, marked by a strong, spiral 

 cord about halfway between the peripheral cord and the insertion of 

 the columella, the spaces which separate it from the peripheral cord 

 on one side and from the columella on the other, appearing as deep, 

 rounded channels. Aperture rather small, irregularly ovate, very 

 strongly channeled anteriorly; posterior angle obtuse; outer lip ren- 



