354 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 40. 



strong sublamellar keels, which are not quite as wide as the spaces that 

 separate them. The first of these is near to the appressed summit, 

 the third quite a bit anterior to the suture, while the second occupies 

 the space midway between these two. In addition to these keels, 

 the whorls are marked by slightly protractive, axial ribs which are 

 equal to the spiral cords in strength. Of these ribs, 16 occur upon 

 the first to fifth, 18 upon the sixth, 20 upon the seventh, 22 upon the 

 eighth, 24 upon the ninth, and 26 upon the penultimate turn. The 

 junctions of the axial ribs and spiral cords form strong, cusp-like 

 tubercles, which are suddenly truncated posteriorly and slope gently 

 anteriorly; the spaces between them are deep, squarish pits. Sutures 

 moderately constricted, showing the peripheral cord on all the turns. 

 Periphery of the last whorl marked by a very strong, spiral keel, the 

 space between which and the first suprapcripheral keel is almost as 

 wide as that separating the supraperipheral keel from the median, 

 and, like that, is crossed by the continuations of the axial ribs which 

 extend prominently to the posterior termination of the peripheral 

 keel. Base marked by a slender, basal fasciole which surrounds the 

 insertion of the columella, the space between the fasciole and the 

 peripheral cord being concave. Aperture irregularly oval, very 

 strongly channeled anteriorly; posterior angle obtuse; outer lip thin, 

 showing the external sculpture within, rendered decidedly sinuous 

 at the edge by the external sculpture; columella short and stout, the 

 edge reflected; parietal wall glazed with a thin callus. 



The type (Cat. No. 213301, U.S.N.M.) comes from California with- 

 out definite designation of locality. It has eleven post-nuclear 

 whorls (having lost the nucleus and probably the first post-nuclear 

 turn) and measures: Length 8.6 mm., diameter 2.4 mm. 



CERITHIOPSIS COLUMNA Carpenter. 



Plate 36, fig. 6. 



Cerlthiopsis columna Carpenter, Rept. Brit. Ass. Adv. Sci., 1864, p. 660; Ann. 

 Mag. Nat. Hist.,ser. 3, vol. 15, 1865, p. 32. 



Shell elongate-conic, light chestnut brown. (Early whorls decol- 

 lated.) Succeeding turns very slightly rounded, marked by three 

 tuberculate spiral keels, of which one is at the summit, another a little 

 above the periphery, and a third a little nearer the posterior than its 

 supra-sutural neighbor. These keels are separated by spiral grooves, 

 which are only about one-third as wide as the keels. In addition to 

 the spiral keels, the whorls are marked by almost vertical axial ribs, 

 which are about two-thirds as strong as the spiral cords and very 

 closely spaced. Of these, 16 occur upon the second and third, 18 

 upon the fourth, 22 upon the fifth and sixth, 24 upon the seventh, 

 26 upon the eighth and 32 upon the penultimate turn. The narrow 

 spaces inclosed between the ribs and spiral cords appear as small, 



