190 



BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



Post-nuclear whorls well rounded, moderately contracted at the 

 sutures and slightly shouldered at the summit, marked by four strong 

 flattened cords which grow successively a little weaker from the sum- 

 mit to the periphery, separated by narrow, deeply incised spiral 

 grooves. Periphery of the last whorl marked l)y a broad, flat cord 

 somewhat wider than the first supra-peripheral one. Base of the 

 last whorl somewhat attenuated anteriorly, well rounded, marked by 

 eleven equal and equally narrow, rounded, spiral cords. In addition 

 to this sculpture, there are many very fine incised spiral lines and 

 decidedly retractive axial lines of growth on the spire and base. 

 Aperture broadly oval, slightly effuse anteriorly, posterior angle 

 acute; outer lip thin, showing the external sculpture within; colu- 

 mella moderately strong, slightly curved, somewhat reflected, com- 

 pletely reenforced by the base, provided w4th a strong fold at its 

 insertion; parietal wall covered by a thin callus. 



The type (Cat. no. 46478, U.S.N.M.) and 124 specimens come from 

 San Diego, California. The type has seven post-nuclear whorls and 

 measures: Length 4.4 mm., diameter 1.8 mm. 



The following specimens have been examined : 



U.S.N.M. 

 cat. no. 



126025 

 46498 



208068 

 46478 

 46477 



127053 

 106520 



Num- 

 ber of 

 speci- 

 mens. 



12 



1 



150 



125 



80 



1 



4 



10 



1 



Locality. 



San Pedro, California 



do 



do 



San Diego, California 



do 



Foot of Ash street, San Diego, California. 



San Diego, California 



Long Beach, California 



San Ignacio Lagoon, Lower California. . . 



Disposition of 

 material. 



U. S. Nat. Mus. 



Do. 



Do. 



Do. 



Do. 

 Oldroyd Coll. 

 Univ. ofCal. 

 U. S.Nat. Mus. 



Do. 



ODOSTOMIA (MENESTHO) HYPOCURTA, new species. 

 Plate 21, fig. 8. 



Shell very elongate-ovate, bluish-white. (Nuclear whorls decol- 

 lated.) Post-nuclear whorls well rounded, marked by five broad, 

 strong, deeply incised spiral grooves, that divide the space between 

 the sutures into raised, flattened keels, which are successively a little 

 wider from the summit to the periphery. Periphery of the last 

 wdiorl marked by a groove similar to those above. Base rather short, 

 moderately rounded, marked by five subequal and subequally spaced 

 spiral grooves which are a little weaker tlian those on the spire. The 

 entire surface of tlie shell is marked by slender lines of growth, and 

 the raised spaces between the spiral grooves are finely spirally stri- 

 ated. Suture strongly impressed. Aperture ? (outer lip fractured) ; 

 columella strong, curved, revolute, its posterior two-thirds reenforced 

 by the base; columellar fold not visible in the aperture. Operculum 

 paucispiral. 



