96 BULLETIN OS, UNITED STATES NATIONAL MUSEUM. 



than the ribs, marked by seven deep pits of uneciual width and une- 

 qual spacing. Periphery of the last whorl marked by a broad plain 

 band. Base well rounded, marked by the very feeble continuations 

 of the axial ribs and nine irregular, wavy, incised spiral lines, the first 

 two of which below the periphery are interrupted. Aperture ovate; 

 posterior angle acute ; outer lip thin, showing the external markings 

 within; columella slender, very oblique, somewhat flexuose and revo- 

 lute, with a slight fold at its insertion. 



The type and three specimens (Cat. no. 162633, U.S.N.M.) were 

 dredged in 2 fathoms off San Diego, California. The type has eight 

 post-nuclear whorls and measures: Length 4.6 mm., diameter 1.2 mm. 



TURBONILLA (PYRGISCUS) CALLIPEPLUM, new species. 

 Plate 9, figs. 11, 11a. 



Shell elongate-conic, rather stout, milk-white. Nuclear whorls 

 two, forming a planorboid spire, whose axis is at right angles to the 

 succeeding turns, in the first of which it is about one-fourth im- 

 mersed. Post-nuclear whorls flattened in the middle, with a strongly 

 sloping shoulder which extends over the posterior fourth between the 

 sutures, forming a decided angle at its anterior termination; slightly 

 contracted at the suture, marked by slender, sinuous, slightly 

 retractive, sublamellar, axial ribs, of which 14 occur upon the first 

 two whorls, 16 upon the third and fourth, 18 upon the fifth, and 20 

 upon the remaining turns. Intercostal spaces varying somewhat in 

 width, about four times as wide as the ribs, marked by a double 

 series of narrow pits, one of which is at the periphery and the other at 

 the anterior termination of the posterior third of the whorls. In 

 addition to these pits there are finely incised lines of varying strength, 

 18 of which occur between the two pits and 9 between the posterior 

 pit and the summit. Sutures well impressed. Periphery of the last 

 whorl slightly angulated. Base marked by the feeble continuations 

 of the axial ribs, which extend a little ways beyond the periphery, 

 and 17 almost equal and almost equally spaced, slender, incised 

 spiral lines. Aperture? (outer lip fractured); columella reflected. 



The type (Cat. no. 122797, U.S.N.M.) was dredged at U. S. Bureau 

 of Fisheries station 2805 in 51 fathoms, on mud bottom, in Panama 

 Bay. It has nine post-nuclear whorls and measures: Length 5.1 

 mm., diameter 1.4 mm. 



TURBONILLA (PYRGISCUS) DINA, new species. 



Plate 9,f\ii. 10. 



Shell elongate-conic, milk-white. Nuclear whorls two and one- 

 half, forming a depressed, helicoid spire, the axis of which is at right 

 angles to that of the succeeding turns, in the first of which it is about 



