664 PROCEEDINGS OF TEE NATIONAL MUSEUM. vol.52. 



which 18 occur upon the first and 16 upon the remaining whorls, 

 except the last, which has 20. These ribs pass f>rominently from the 

 shoulder to the peripheral sulcus. In addition to the axial sculpture 

 the first 4 turns are crossed by 4 equal and equally spaced, flattened 

 spiral cords, which are about as wide as the spaces that separate 

 them. On the rest of the turns the subperipheral cord comes into 

 the suture and on the penultimate whorl forms a well- developed 

 5-spiral cord on the spire. The spaces enclosed by the axial ribs 

 and spiral cords are deeply impressed oblong pits, while the junction 

 of the ribs and spiral cords form well-rounded tubercles. Suture of 

 the early turns, where the fifth spiral is still below the summit of 

 the succeeding turn, deeply channeled, less so on the later whorls. 

 Periphery of the last turn strongly rounded. Base short, inflated, 

 strongly rounded, marked by nine strong, rounded, spiral cords which 

 are almost equal and as wide as the spaces that separate them. The 

 grooves between these spiral cords are crossed by numerous slender 

 axial riblets. Aperture oval; posterior angle obtuse; outer lip thin 

 rendered sinuous by the external sculpture ; inner lip slender, thin, 

 somewhat revolute, provided with a strong oblique fold at its inser- 

 tion. Parietal wall covered by a thin callus. 



The type, Cat. No. 267743« U.S.N.M. was dredged in shallow water 

 in Santa Maria Bay, Lower California. It has seven postnuclear 

 whorls and measures — length, 3.8 mm. ; diameter, 1.3 mm. 



Another specimen, Cat. No. 268635 U.S.N.M. was dredged by the 

 U. S. Bureau of Fisheries steamer Albatross at station 5678, off 

 Eedondo Point, Magdalena Bay, Lower California, in 13^ fathoms, 

 on broken shell bottom. 



ODOSTOMIA (CHRYSALLIDA) SANTAMARIENSIS, new Bpecies. 



Plate 46, fig. 1. 



Shell stout, oval, yellowish white. Nuclear whorls decollated, the 

 pit left in the apex of the type shows that it must have been strongly 

 immersed in the first of the postnuclear turns. Postnuclear whorls 

 strongly rounded, feebly shouldered at the summit, marked by 

 rather slender axial ribs, of which 20 occur upon all the turns. In 

 addition to the axial ribs the whorls are marked by 5 spiral cords, 

 which are a little stronger than the ribs. The cords are about as 

 wide as the spaces that separate them, their junctions with the ribs 

 form rounded tubercles, while the spaces inclosed between them are 

 strongly impressed concaved pits. Suture not channeled. Base 

 rather long, somewhat inflated, well rounded, marked by 10 strong 

 spiral cords, which decrease in size gradually and regularly from the 

 periphery to the umbilical chink. The grooves between these spiral 

 cords, which are about equal to the cords in width, are armed by 



