660 PROCEEDINOS OF THE NATIONAL MUSEUM. vol.52. 



Postnuclear whorls strongly roundly shouldered at the summit, flat- 

 tened in the middle, crossed by strong sublamellar, slightly protrac- 

 tively slanting axial ribs, of which 16 occur upon the first and second 

 and 18 upon the remaining turns, excepting the last, which has 20. 

 Intercostal spaces about one and one-half times as wide as the ribs, 

 crossed by 11 incised spiral lines, of which the first three are mere 

 striations, while the fourth and the peripheral are wider than the 

 rest, which are about half their width. Suture rather strongly con- 

 stricted. Periphery of the last whorl well rounded. Base short, 

 narrowly umbilicated, marked by the feeble continuations of the axial 

 ribs, which become evanescent before reaching the middle of the 

 base and seven equal incised spiral lines, of which the first three 

 occupy about as much space as that separating the third from the 

 fourth; the rest become successively closer spaced anteriorly. The 

 space between the first basal line and the peripheral pit is a very 

 broad smooth band. Aperture very broadly oval; posterior angle 

 acute; outer lip thin, showing the external sculpture within; inner 

 lip thin, slightly curved and somewhat revolute, provided with a 

 weak oblique fold at its insertion; parietal wall covered with a thick 

 callus. 



The type. Cat. No. 268T33 U.S.N.M., was dredged by the U. S. 

 Bureau of Fisheries steamer Albatross at station 5678 off Redondo 

 Point, Magdalena Bay, Lower California, in 13| fathoms, on broken- 

 shell bottom. It has 9J postnuclear whorls and measures — length, 

 5.5 mm. ; diameter, 1,6 mm. 



TURBONIIiLA (CINGULINA) URDENETA, new species. 



Plate 45, fig. 1. 



Shell elongate-conic, yellowish white, semi-translucent. Nuclear 

 whorls deeply obliquely immersed in the first of the succeeeding turns 

 above which only the tilted edge of the last volution projects. Post- 

 nuclear whorls well rounded, the first smooth, the second with 2, 

 and the next three with 3 spiral keels, while the rest have 4 between 

 the summit and the suture. The summits of the whorls are feebly 

 shouldered; the first spiral keels fall on the anterior termination of 

 the posterior third of the whorls between the summit and the suture, 

 the space between the summit and this keel being concave. The 

 second and third keels are as strong as the first and are separated 

 from each other by a space a little more than half the width of that 

 between the first and the summit, while the fourth keel is separated 

 from the third by only half that space. The entire surface of the 

 spire, excepting the summit of the keels is crossed by numerous 

 closely spaced very slender axial threads and microscopic spiral 

 striations. Suture strongly constricted. Periphery well rounded. 



