344 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



well rounded, marked between the sutures by 4 strong, narrow spiral 

 cords, which divide the space between the sutures into 5 almost equal 

 parts, that between the summit and the first cord being a little wider 

 than the rest. In addition to the spiral cords, the whorls are marked 

 by slender axial riblets, which are about as strong as the spu-al cords. 

 Of these riblets, about 24 occur upon the first and second, and about 

 26 upon the penultimate, turn. The spaces inclosed between the 

 spiral cords and the axial riblets are elongated pits, having their 

 long axes parallel with the spiral sculpture. In addition to the 

 above sculpture, the entire surface of the shell is marked by numerous 

 very fine, closely spaced spiral striations. Suture strongly con- 

 stricted. Periphery of the last whorl marked by a sulcus as wide 

 as that which separates the first supraperipheral cord from its pos- 

 terior neighbor. Base moderately long, scarcely produced ante- 

 riorly, well rounded, marked by seven spiral cords, which grow 

 successively weaker and closer spaced from the periphery to the 

 umbiUcal region. Aperture moderately large, broadly oval; posterior 

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

 inner hp slender, curved, and reflected, the posterior edge touching 

 the body whorl; parietal wall covered with a moderately thick callus, 

 which renders the peritreme complete. 



The type (Cat. No. 160114, U.S.N.M.) comes from Monterey, 

 California. It has 3| post-nuclear whorls, and measures: Length, 

 2.3 mm., diameter 1.1 mm. Cat. No. 213679, U.S.N.M., contains a 

 specimen from Sitka Harbor, Alaska; Cat. No. 46174, U.S.N.M., 

 contains tliree from Monterey, Cahfornia; Cat. No. 126719, U.S.N.M., 

 contains two, also from Monterey; and Cat. No. 219742, U.S.N.M., 

 six from Pacific Grove. 



ALVANIA EXCURVATA Carpenter. 

 Plate 30, fig. 6. 

 fAlvania excurvata Carpenter, Cat. Maz. Shells, 1856, p. 359. 



Shell elongate-conic, brownish gray. Nuclear whorls 2, smooth. 

 Post-nuclear whorls well rounded, marked by slender, axial ribs, 

 of wliich about 16 occur upon the fu'st, 18 upon the second, 20 upon 

 the third and fourth, and 30 upon the penultimate turn. In addi- 

 tion to the axial ribs, the whorls are marked by slender spiral cords, 

 of which 2 occur upon the first and second, 3 upon the third and 

 fourth, and 5 upon the penultimate turn between the sutures. The 

 spaces inclosed between the cords and ribs are squarish pits. Suture 

 strongly constricted. Periphery of the last whorl well rounded. 

 Base moderately long, scarcely attenuated, well rounded, marked 

 by the feeble continuations of the axial ribs and three sphal cords. 

 Aperture oval; outer lip tlfin; inner lip strongly curved and slightly 



