402 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 40. 



Specimens examined. 



Catalogue 

 No. 



46166 



160891 



195177 



203677 



i 224860 



23756 



56906 



56907a 



160076b 



153443 



195164 



109516 



195165 



162675 



105591 



Locality. 



Monterey, California 



do 



do 



Santa Barbara, California 



Catalina Island, California 



do 



Catalina Island, California (described and figured). 



Catalina Island, California 



do 



San Pedro, California 



Whites Point, San Pedro Bay, California 



Terminal Island, California 



Pacific Beach, California 



La Jolla, California 



San Diego, California 



Number of 

 specimens. 



•Type. 

 BITTIUM (LIROBITTIUM) CATALINENSE Bartsch. 



Plate 51, fig. 1. 



Bittium catalinensis Bartsch, Smiths. Misc. Coll. (Quarterly Issue), vol. 50, 1907, 

 pt. 4, p. 28, pi. 57, fig. 13. 



Shell elongate-conic, milk-white. Nuclear whorls a little more than 

 one, marked by two strong spiral cords which divide the turns into 

 three equal areas. Post-nuclear whorls shouldered at the summit, 

 marked by three nodulose spiral keels ; one of these, which is a little 

 below the summit, is less strongly developed than the other two on 

 all but the last turn; on this turn it is practically equal to the others. 

 In addition to the spiral keels, the whorls are marked by rather strong, 

 well-rounded axial ribs which are about two-thirds as wide as the 

 spaces which separate them. Of these ribs, 16 occur upon the first 

 to fifth, 18 upon the sixth and seventh, 20 upon the eighth, and 24 

 upon the penultimate turn. The intersections of the axial ribs and 

 the spiral cords form strong cusp-like nodules, which are suddenly 

 truncated posteriorly and slope gently to the succeeding cord anteri- 

 orly. The space between the summit and the truncated end of the 

 first row of tubercles forms a strong shoulder. The spaces inclosed 

 between the spiral keels and the axial ribs are moderately impressed 

 rounded pits. Sutures strongly constricted, showing the greater part 

 of the peripheral cord on all the turns. Periphery and base of the 

 last whorl marked by five spiral cords which grow successively weaker 

 from the periphery to the umbilical area. These cords are truncated 

 on the posterior .margin and slope gently anteriorly until they fuse 

 with the general surface of the shell. Aperture irregular, channeled 

 anteriorly; posterior angle obtuse; outer lip rendered sinuous by the 

 external sculpture; columella oblique, somewhat twisted; parietal 

 wall glazed with a thin callus. 



