NO. 2193. WEST AMERICAN MARIXE M0LLVSKS—BART8CII. 671 



third spiral keel, marked by rather feeble axial ribs, which are 

 slightly retractive. Of these ribs, 16 occur upon the first and second, 

 18 upon the third, 20 upon the fourth, and 24 upon the penultimate 

 whorl. The spiral sculpture consists of three strong keels which are 

 a little wider than the spaces that separate them and considerably 

 wider than the axial ribs. The first of these is at the summit, the 

 second one midway between the first and third, while the third is a 

 little posterior to the suture. The junction of the axial ribs and 

 spiral keels renders the spiral keels tubercular. The tubercles on the 

 first cord are oval with their long axis corresponding to the axial 

 sculptur'e. The tubercles on the median cord are truncated both 

 anteriorly and posteriorly, but sloped a little more gently anteriorly, 

 while the tubercles on the third cord are truncated abruptly pos- 

 teriorly and gently anteriorly. Suture narrowly channeled. Pe- 

 riphery of the last whorl marked by a deep spiral sulcus, which is 

 as wide as that separating the third from the median cord on the 

 spire. This groove is crossed by the continuations of the axial rib 

 which terminate at its anterior margin. Base moderately long, 

 marked by a strong spiral keel immediately anterior to the peripheral 

 sulcus, and another a little less strong in the middle of the space be- 

 tween the insertion of the columella and this keel. This middle keel 

 is bordered on each side by a deep sulcus. In addition to this, the 

 entire spire and base also bear exceedingly fine spiral striations and 

 incremental lines. Aperture of irregular outline, decidedly chan- 

 neled anteriorly; posterior angle obtuse; outer lip thick within, thin 

 at the edge where it is rendered sinuous by the external sculpture ; 

 columella very stout, almost vertical; inner lip moderately strong, 

 reflected over and adnate to the base; parietal wall covered with a 

 thick callus which renders the peritreme complete. 



The type, Cat. No. 204128, U.S.N.M., was collected by the U. S. 

 Bureau of Fisheries steamer Albatross, on the shores of Panama 

 Bay. It has six postnuclear whorls and measures — length, 2.9 mm. ; 

 diameter 1.0 mm. 



CERITHIOPSIS OROVILLENSIS Dickerson. 



Cerithiopsis orovillensis Dickerson, Bull. Dept. Geol. Univ. Cal., vol. 9, No. 

 17, 1916, p. 489, pi. 39, fig. 7. 



The type comes from the Eocene Tejon formation at the University 

 of California locality 2225, south side of Oroville, South Table 

 Mountain. It has nine whorls and measures — length, 6 mm.; diam- 

 eter, 2 mm. 



CERITHIOPSIS (CERITHIOPSIS) DUMBLEI Dickerson. 



Cerithiopsis dumblei Dickerson, Bull. Dept. Geol. Univ. of Cal., vol. 9, No. 

 17, 1916, p. 489, pi. 38, fig. 12. 



The figured type has nine whorls; the specimen measures, length, 

 9.5 mm. 



