WEST AMERICAN PYRAMIDELLID MOLLUSKS. 85 



TURBONILLA (PYRGISCUS) ARAGONI, new species, 

 riateO, figs. 12, I2a. 



Shell elongate-conic, anterior half of whorls chestnut brown, the 

 rest, flesh colored. Nuclear whorls two, forming a depressed helicoid 

 spire, whose axis is at right angles to that of the succeeding turns, in 

 the first of which it is one-fifth immersed. Post-nuclear whorls well 

 rounded, slightly contracted at the suture, appressed at the summit, 

 marked by acute vertical axial ribs, of which 1 6 occur upon the first to 

 seventh, 20 upon the eighth, and 26 upon the penultimate turn. 

 Intercostal spaces about two and one-half times as wide as the ribs, 

 marked by fine lines of growth and seven strongly incised spiral 

 grooves, and numerous exceedingly fine, spiral striations. Sutures 

 slightly contracted. Periphery of the last whorl slightly angulated, 

 marked by a narrow plain band. Base short, well rounded, marked 

 b}^ fifteen well incised and numerous very fine spiral lines. Aperture 

 rhomboidal, posterior angle obtuse; outer lip thin, showing tlie 

 external markings w^ithin; columella slender, slightly curved. 



The type (Cat. no. 206867, U.S.N.M.) w^as dredged by Mr. S. S. 

 Berry, in 29 fathoms, on sandy bottom, off New Monterey, Monterey 

 Bay. It has ten post-nuclear whorls and measures: Length 7.2 mm., 

 diameter 2 mm. 



TURBONILLA (PYRGISCUS) RECTA, new species. 



Plate 7, figs. 12, i2a. 



Shell broadly conic, milk-w^hite. Nuclear whorls small, two 

 and one-half, depressed, helicoid, having their axis at right angles 

 to that of the succeeding turns, in the first of which they are about 

 one-third immersed. Post-nuclear whorls slightly rounded, some- 

 what exserted, weakly shouldered at the summit, marked by slender, 

 protractive axial ribs, of which 22 occur upon the second, 24 upon the 

 third, 28 upon the fourth and fifth, and 30 upon the penultimate whorl. 

 Intercostal spaces about as ^nde as the ribs, marked by eight equal and 

 equally spaced spiral series of pits. Sutures strongly marked, crenu- 

 lated by the ribs. Periphery of the last whorl well rounded, appear- 

 ing as a broad plain band, marked only by the feeble continuations 

 of the axial ribs. Base short,' well rounded, marked by ten equal 

 and almost equally spaced spiral striations. Aperture oval; pos- 

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

 within ; columella slender, strongly curved, slightly revolute, with a 

 weak fold at its insertion. 



The typo (Cat. no. 162635, U.S.N.M.) comes from Point Abreojos, 

 Lower California. It has seven post-nuclear whorls and measures: 

 Length 3.6 mm., diameter 1.3 mm. Another specimen (Cat. no, 

 162634, U.S.N.M.) comes from San Diego, CaHfornia. 

 2565— Bull. 08—09 7 



