WEST AMEEICAN PYRAMIDELLID MOLLUSKS. 123 



TURBONILLA (DUNKERIA) HIPOLITENSIS, new species. 

 Plate 12, figs. 8, 8a. 



Shell milk-white, with a light yellow narrow band midway between 

 the sutures. Nuclear whorls small, two and one-half, forming a 

 depressed helicoid spire, whose axis is at right angles to that of the 

 succeeding turns, in the first of which it is about one-third immersed. 

 Post-nuclear whorls moderately rounded, slightly shouldered at the 

 summit but very slightly protracted at the suture, marked by mod- 

 erately strong, rounded, retractive axial ribs, of which 18 occur upon 

 the second, 20 upon the tliird, 24 upon the fourth and fifth, and 30 

 upon the penultimate turn. Intercostal spaces as wide as the ribs, 

 crossed by five series of broad spiral pits, which are not quite as wide 

 as the five raised cords which they bound, and which render the ribs 

 somewhat nodulose at their junction. Periphery and base of the 

 last whorl well rounded, the latter marked by six spiral cords and a 

 feeble continuation of the axial ribs. Aperture oval; posterior 

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

 columella moderately strong, curved, reenforced by the base. 



The type and two additional specimens (Cat. no. 206889, U.S.N.M.) 

 comes from San Hipolito Point, Lower Cahfornia. The type has 

 seven post-nuclear whorls and measures: Length 3.3 mm., diameter 

 L2 mm. 



TURBONILLA (DUNKERIA) EXCOLPA, new species. 

 Plate 12, figs. 4, 4a. 



Shell wax yellow on the early whciis, ranging t ; chestnut 1 - 

 the last. Nuclear whorls tw^o and cne-half, fcrmii g a depi 

 coid spire, whose axis is at right angles to that of the succeed., 

 in the first of which it is about one-tliird immersed. Post-uuclear 

 whorls well rounded, marked by well-developed, narrow, rounded, 

 almost vertical axial ribs, of which 24 occur upon the first to third, 

 26 upon the fourth, 28 upon the fifth, and about 36 upon the penulti- 

 mate turn. Intercostal spaces about as wide as the ribs, crossed by 

 five series of spiral pits which are as wide as the five raised spaces 

 wliich they separate. The junction of these raised cords with the 

 ribs renders them nodulous. Sutures constricted. Periphery of the 

 last whorl and base well rounded, the latter marked by seven spiral 

 cords. Aperture oval; posterior angle acute; outer lip thin, showing 

 the external sculpture within columella slender, somewhat twisted, 

 reenforced by the base. 



The type (Cat. no. 206892 U.S.N.M.) comes from the Gulf of Cali- 

 fornia. It has seven post-nuclear whorls and measures: Length 

 3.7 mm., diameter 1.1 mm. 



