WEST AMERICAN PYRAMIDELLTD MOLLUSKS. 91 



The type (Cat. no. 56791, U.S.N.M.) is labeled "South America;" 

 without specific designation of locality. It has lost the nucleus 

 and probably the first post-nuclear turn. The thirteen remaining 

 measure: Length 9.9 mm., diameter 2.1 mm. 



Named for Thomas Nuttall. 



TURBONILLA (PYRGISCUS) MACRA, new species. 

 Plate 8, figs. 10, 10a. 



Shell very small, subcylindric in the middle, tapering rapidly at the 

 apex, early whorls wax-yellow, later ones white, with a very broad, 

 wax-yellow band at the periphery, which extends above the sutures 

 and on the base. Xuclear whorls very small, at least two, forming a 

 depressed helicoid spire, which is obliquely half immersed in the first 

 of the succeeding turns. Post-nuclear whorls moderately rounded at 

 first, later flattened, ornamented by almost straight, vertical, slender, 

 well-developed axial ribs, of which there are 22 upon the first, 24 upon 

 the second to fifth, and 25 upon the penultimate turn. Intercostal 

 spaces about as wide as the ribs, marked by five equal but not equally 

 spaced series of spiral pits. The first four of these above the periph- 

 ery are equally spaced; the fifth is a little nearer to the summit of 

 the whorl than its neighbor. Sutures well impressed. Periphery of 

 the last whorl well rounded, marked by the feeble continuations of the 

 axial ribs. Base of the last whorl prolonged, well rounded, marked 

 by six equally spaced and equall}^ strongly incised spiral lines. Aper- 

 ture ovate; posterior angle acute; outer lip thin, showing the external 

 markings within ; columella moderately strong, reenf orced by the base, 

 provided with a weak fold at its insertion; parietal wall covered \vith 

 a thin callus. 



The type (Cat. no. 162632, U.S.N.M.) and five other specimens were 

 obtained at Point Abreojos, Lower California. The type has seven 

 post-nuclear whorls, and measures: Length 3.2 mm., diameter 

 0.9 mm. 



TURBONILLA (PYRGISCUS) ANGUSTA Carpenter. 

 Plate 8, fig. 6. 

 Chrysallidaangusta CAKFEtiTER, Ann. Mag. Nat. Hist., (3dser.,) vol. 14, 1864, p. 47. 



Shell elongate-conic, slender, crystalline. (Nuclear whorls decol- 

 lated.) Post-nuclear whorls slightly rounded, moderately contracted 

 at the sutures, slightly shouldered at the summit, marked by low, 

 rounded, axial ribs, of which 16 occur upon all but the penultimate 

 whorl, upon which there are 18. Intercostal spaces about one and 

 one-half times as wide as the ribs, marked b}" 6 equal and equally 

 spaced spiral lirations between the sutures. Base somewhat pro- 

 duced, moderately rounded, marked by the feeble continuations of 

 the axial ribs and nine spiral lirations which become successively 

 weaker from the periphery to the umbilical area. Aperture oval; 



