134 BULLETIN 68; UNITED STATES NATIONAL MUSEUM. 



the second and third, and 18 upon the penuhimate turn. Intercos- 

 tal spaces somewhat wider than the ribs, strongly impressed. Periph- 

 ery of the last whorl marked by a broad, low keel. Base with a 

 strongly raised tumescence about the umbilical area, the space 

 between which and the peripheral keel appears slightly concave. 

 The axial ribs continue weakly over the base. A strong varix 

 appears on the last whorl, between two axial ribs, and extends from 

 the summit to the umbilical chink. Aperture suboval; posterior 

 angle obtuse; outer lip thin, showing the external sculpture within; 

 columella strong, straight, and decidedly revolute; parietal wall 

 covered by a thin callus. 



The type (Cat. no. 160484, U.S.N.M.) comes from San Pedro, 

 California. It has five and one-half post-nuclear whorls, and meas- 

 ures: Length 3 mm., diameter 1.4 mm. 



Subgenus SALASSIA De Folin. 



Salassia De Folin, Const, d. Chemnitzidae, 1885, p. 15. 



Shell pupiform, whorls not inflated, marked by axial ribs which 

 extend from the tabulated summit of the whorl to the umbilical area. 

 Varices absent. 



Type. — Salassia tropidita Dall and Bartsch. 



KEY TO THE SPECIES OP THE SUBGENUS SALASSIA. 



Summit of the whorls tabulated tropidita, y>. 134. 



Summit of the whorls rounded scalariformis, p. 135. 



ODOSTOMIA (SALASSIA) TROPIDITA, new name. 



Plate 13, fig. 3. 



Salassia carinata De Folin, Fonds de la Mer, vol. 2, 1872, p. 168, pi. 6, fig. 6; 

 not Scalenostoma carinata Deshayes, 1863, nor Odostomia carinata H. Adams, 

 1873. 



Shell pupiform, white. Nuclear whorls one and one-half, forming 

 a moderately elevated 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 moderately rounded, some- 

 what contracted at the sutures, strongly tabulated on the summits, 

 marked by rounded, weak, axial ribs of which 8 occur upon the 

 first and second, 10 upon the third, 12 upon the fourth and fifth, 

 and 14 upon the penultimate turn. Intercostal spaces broad and 

 shallow. Periphery of the last whorl and base well rounded, marked 

 by the continuation of the ribs. Aperture broadly oval; outer lip 

 thin; columella slender, slightly curved. 



De Folin's type comes from Isle of Pearls, Bay of Panama. It has 

 seven post-nuclear whorls, and measures: Length 2.5 mm., diame- 

 ter 1.2 mm. 



