WEST AMERICAN PYRAMIDELLID MOLLUSKS. 79 



TURBONILLA (PYRGISCUS) PEQUENSIS, new species. 



Plate 7, figs. 5, 5f/. 



Shell slender, light yellow, with a broad golden l^and encirchng the 

 whorls in the middle between the sutures, and another a Uttle wider 

 immediately posterior to the periphery. Nuclear whorls two, plan- 

 orboid, having their axis almost at right angles to that of the suc- 

 ceeding turns, in the first of which they are about one-fourth im- 

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

 sloping shoulder, which occupies about one-fifth of the space between 

 the sutures; somewhat contracted at the ]:)eriphery, marked by 

 moderately strong, slightly protractive axial ribs, which are strongest 

 at the angle of the shoulder and terminate at the periphery. Of these 

 ribs there are 14 upon the first to third and 16 upon the remaining 

 turns. Intercostal spaces almost as wide as the ribs, shallow, marked 

 by eight equal, strongl}^ incised, but unecpially spaced spiral grooves; 

 the three immediately posterior to the periphery being a httle more 

 closely spaced than the rest. Two feebly incised fine lines divide 

 the space between the summit and the first strong line and that 

 between the first and second. These fine lines are best shown on 

 the last whorls. Sutures well impressed. Base short, well rounded, 

 marked by about a dozen very fine, wavy spiral striations. Aperture 

 rhomboid; outer lip thin, showing the external sculpture within; 

 columella somewhat twisted, sHghtly revolute, pro\dded with an 

 oblique fold at its insertion. 



The type (Cat. no. 97019, U.S.N.M.) has eight post-nuclear whorls, 

 and measures: Length 4.6 mm., diameter 1.8 mm. It was collected 

 at U. S. Bureau of Fisheries station 2834, near Point Abreojos, in 12 

 fathoms, on sand bottom, ofl^ Lower CaHfornia. 



TURBONILLA (PYRGISCUS) NUTTINGI, new species. 



Plate 7, figs. 13, 13a. 



Shell long and slender, wax yellow on the posterior half between the 

 sutures, light brown on the anterior and the periphery. Nuclear 

 whorls large, 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 one-fifth immersed. Post-nuclear whorls 

 moderately well rounded, slightly shouldered at the summit, marked 

 by strong, broad, well rounded, somewhat jirotractive axial ribs, of 

 which 20 occur upon the first to sixth, 22 upon the seventh to mnth, 

 and 24 upon the penultimate turn. These ribs extend prominently 

 from the summit to the periphery of the whorls, but do not cross the 

 latter. Intercostal spaces very narrow, not more tlian half the mdth 

 of the ribs; anterior half between the sutures marked by five equal 

 and equally spaced s])iral grooves; ])osterior lialf marked by two 

 which equal those on the anterior half in strength, but are a Httle 



