654 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 52. 



eleventh are about twice as wide as these, and the ninth and thir- 

 teenth are double the width of the last. The space between the 

 summit and the first is as wide as the space between the eighth and 

 ninth, which is doubly as wide as that separating the first five lines, 

 which are subequally spaced. The spaces between the eighth and 

 ninth, ninth and tenth, tenth and eleventh, and eleventh and twelfth 

 increase steadily in width, the space between the first of this series 

 being about one-half as wide as that separating the last. Suture 

 moderately constricted. Periphery of the last whorl angulated. Base 

 short, well rounded, marked by the feeble continuations of the axial 

 ribs, which become evanescent before reaching the middle of the 

 base, and 12 feebly incised, slender, wavy, spiral striations, which 

 become successivelj'' weaker and closer spaced from the periphery 

 toward the umbilical area. Aperture subquadrate; posterior angle 

 obtuse; outer lip thin; inner lip slender, slightly twisted, provided 

 with a very oblique fold a little anterior to its insertion; parietal 

 Avail glazed with a thin callus. 



The type and an additional specimen, Cat. No. 268625 U.S.N.M. 

 was dredged along the shore of Santa Maria Bay, Lower California. 

 It has 8^ postnuclear whorls and measures — length, 5.2 mm.; di- 

 ameter, 1.6 mm. 



TURBONILLA (PYRGISCUS) MARIANA, new species. 



Plate 45, fig. 9. 



Shell very slender, elongate conic, light honi yellow with the 

 anterior half of the base and a narrow band about one-fifth of the 

 width of the space between the sutures pale brown. The band is 

 situated about its own width posterior to the periphery. Nuclear 

 whorls decollated. Postnuclear whorls flattened very high between 

 the sutures, narrowly shouldered at the summit, marked by closely 

 crowded, quite regular, vvell rounded, almost straight, slightly pro- 

 tractive axial ribs of which 18 occur upon the first four of the re- 

 maining turns; 20 upon the fifth to seventh; 22 upon the eighth, and 

 26 upon the penultimate whorl. Intercostal spaces a little narrower 

 than the ribs, marked by 13 strongly incised, subequal and subequally 

 spaced pits. Suture moderately constricted. Periphery of the last 

 whorl well rounded. Base attenuated, well rounded, marked by the 

 feeble continuation of the ribs which reach to the umbilical chink 

 and five equal and equally spaced, moderately broad, shallow, incised 

 lines of a rust brown color. Aperture elongate oval ; posterior angle 

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

 lip slender, moderately curved, reflected over and adnate to the 

 attenuated base for two-thirds of its length and pro^^ded with a 

 strong oblique fold at its insertion ; parietal wall covered by a thick 

 callus. 



