WEST AMERICAN PYRAMIDELLID MOLLUSKS. 133 



It is a curious shell, entirely different from anything else that we 

 have seen. Unfortunately the outer siu-face is too badly worn to 

 permit of a positive statement regarding its finer markings. 



SALASSIELLA, new subgenus. 



Shell pupiform, whorls inflated, marked by axial ribs which extend 

 undiminished from the summit to the umbilical area. Varices strong, 

 irregularly distributed. 



Type. — Odostomia (Salassiella) laxa Dall and Bartsch. 



KEY TO THE SPECIES OF THE SUBGENUS SALASSIELLA. 



Summit of the whorls rounded laxa. 



Summit of the whorls tabulated » richi. 



ODOSTOMIA (SALASSIELLA) LAXA, new species. 



Plate 13, figs. 8, 8a. 



Shell pupiform, milk-white. Nuclear whorls at least two, small, 

 forming a depressed helicoid spire, whose axis is at right angles to 

 that of the succeeding turns, in the first of which it is about two- 

 thirds immersed. Post-nuclear whorls inflated, contracted at the 

 sutures, and strongly roundedly shouldered at the summit, marked 

 by lamellar, flexuose axial ribs, which are only feebly expressed on 

 the first. On the second there are 18, on the third 20, 22 upon the 

 fourth, and 28 upon the penultimate turn, upon which there is a 

 strong varix. Intercostal spaces about one and one-half times as 

 wide as the ribs, well impressed. Sutures constricted. Periphery 

 and base of the last whorl well rounded, marked by the continua- 

 tions of the axial ribs. Aperture broadly oval; posterior angle 

 obtuse; outer lip thin, showing the external sculpture within; col- 

 umella slender, strongly curved, and slightly revolute, provided with 

 a weak fold at its insertion. 



The type and another specimen (Cat. no. 106512, U.S.N.M.) comes 

 from Scammon Lagoon, Lower California. It has six post-nuclear 

 whorls, and measures: Length 4.3 mm., diameter 1.7 mm. Another 

 specimen (Cat. no. 286893, U.S.N.M.) comes from San Diego, Cali- 

 fornia. 



ODOSTOMIA (SALASSIELLA) RICHI, new species. 

 Plate 13, figs. 6, 6a. 



Shell small, broadly conic, white. Nuclear whorls three, forming 

 a depressed helicoid spire, whose axis is at right angles to that of 

 the succeeding turns, in the first of which it is about one-third 

 immersed. Post-nuclear whorls strongly rounded, moderately con- 

 tracted at the suture, broadly tabulated at the shoulder, marked by 

 strong, lamellar, axial ribs, of which 16 occur upon the first, 14 upon 

 2565— Bull. 68—09 10 



