no. 1826. M0LLUSK8 OF THE GENUS BITTIUM—BARTSCIL 409 



sculpture; columella stout, flexuose, and reflected; parietal wall cov- 

 ered with a thick callus. 



The type (Cat. No. 196209, U.S.N.M.), which has lost the nucleus 

 and probably the first two post-nuclear turns, has twelve whorls 

 remaining, which measure: Length 13.3 mm., diameter 3.8 mm. The 

 type was collected in drift in Lower California. Two other specimens 

 (Cat. No. 195161, U.S.N.M.) come from Destruction Island, Wash- 

 ington. Cat. No. 198101, U.S.N.M., contains 2 specimens labeled 

 "West Coast," without specific locality. The distribution of this 

 species is rather peculiar. 



Named for Mrs. Ida S. Oldroyd. 



BITTIUM FETELLUM, new species. 

 Plate 51, fig. 4. 



Shell moderately large, elongate-conic, light yellow. (Nuclear 

 whorls decollated in all our specimens.) Post-nuclear whorls well 

 rounded, slightly shouldered at the summit, marked by three slender, 

 spiral keels, which divide the space between the sutures into four 

 equal areas. (In addition to the three spiral keels, there is a tend- 

 ency in many of the specimens to have feeble, intercalated cords 

 between the stronger ones.) The axial sculpture consists of decidedly 

 curved, slender ribs, of which 20 occur upon the fourth post-nuclear 

 whorl in the type, 22 upon the fifth, and about 36 upon the penul- 

 timate turn. The spaces inclosed between the ribs and the spiral 

 cords are large, shallow, squarish pits on all the turns but the last; 

 on this they are much longer than broad, their long axes coinciding 

 with the axial sculpture. The intersections of the ribs and spiral 

 cords form slender, sharp cusps. Sutures strongly constricted. 

 Base of the last whorl moderately long, slightly curved, marked by 

 four spiral cords, of which the two middle ones are equal and stronger 

 than the others. Entire surface of spire and base marked by nu- 

 merous strong lines of growth. Aperture large, channeled anteriorly; 

 posterior angle obtuse; outer lip thin, rendered sinuous by the exter- 

 nal sculpture; columella very oblique, curved, and reflected; parietal 

 wall glazed with a thick callus. 



The type and 28 specimens (Cat. No. 198617, U.S.N.M.) were 

 dredged in 16 fathoms off Catalina Island, California. The type has 

 lost the nuclear whorls; the seven remaining measure: Length 9.3 

 mm., diameter 3.5 mm. 



BITTIUM DECUSSATUM Carpenter. 

 Plate 52, fig. 2. 

 Cerithiopsis decussata Carpenter, Cat. Mazatlan Shells, 1857, p. 445. 



Shell elongate-conic, yellowish-white banded with reddish-brown 

 at the base. Nuclear whorls decollated. Post-nuclear whorls 

 marked by three strong, spiral keels, of which the first is slightly 



