WEST AMERICAN PYRAMIDELLID MOLLUSKS. 57 



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

 columella rather long, almost straight, slightly revolute; parietal wall 

 marked by a faint callus. 



The type and two additional specimens (Cat. no. 206860, U.S.N.M.) 

 were obtained at U. S. Biu-eau of Fisheries station 2823, in 26| 

 fathoms, on broken-shell bottom, off La Paz, in the Gulf of California. 

 The type has 8 post-nuclear whorls and measures: Length 3.2 mm., 

 diameter 0.8 mm. Cat. no. 163251, U.S.N.M., contains a specimen 

 dredged at U. S. Bureau of Fisheries station 2822, in 21 fathoms, off 

 La Paz, Lower California. Cat. no. 206861, U.S.N.M., has five 

 specimens dredged at U. S. Bureau of Fisheries stations 2826 to 

 2828, in 9^ to 10 fathoms, off Ceralvo Island, Lower California. 



TURBONILLA (STRIOTURBONILLA) IMPERIALIS, new species. 



Plate 4, figs. 2, 2a. 



Shell elongate-conic, milk-white, with a narrow, faint yellow band 

 in the middle of the whorls between the sutm"es. Nuclear whorls at 

 least two, depressed, helicoid, having their axis at right angles to that 

 of the succeeding turns, in the first of which they are about one-half 

 immersed. Post-nuclear whorls well rounded, depressed at the 

 summit, somewhat contracted at the sutures, marked by slender, 

 almost vertical axial ribs, of which 20 occiu" upon the first and second, 

 22 upon the third, 24 upon the fourth, 26 upon the sixth and penulti- 

 mate turn. Intercostal spaces are twice as wide as the ribs, marked 

 by a series of moderately strong pits at the periphery, and about 

 twenty-six well incised, equal and subequally spaced spiral striations, 

 which pass up on the side of the ribs but do not cross their summits. 

 Periphery of the last whorl angulated. Base short, well rounded, 

 marked by the very feeble continuations of the axial ribs and about 

 twelve equally strong, slender, wavy, spiral striations. Aperture 

 defective, rhomboidal ? 



The type (Cat. no. 206862, U.S.N.M.) comes from Panama. It has 

 8 post-nuclear whorls and measures: Length 3.3 mm., diameter 

 1.1 mm. 



TURBONILLA (STRIOTURBONILLA) SMITHSONI, new species. 



Plate 4, figs. 10, 10«. 



Shell very regularly conic, wax yellow, the area from a little above 

 the suture to the middle of the whorls between the sutiu-es a little 

 higher than the rest. Nuclear whorls small, at least two-thirds 

 obliquely immersed in the first post-nuclear turn, beyond the outline 

 of which it extends some on the left side. Post-nuclear whorls 

 decidedly flattened, very slightly shouldered at the summit, scarcely 

 at all contracted at the periphery, marked by rounded, low, poorly 

 developed, axial ribs, of which 18 occur upon the first and second, 22 



