WEST AMERICAN PYKAMIDKLJ JI) MOLLl'SKS. 45 



TURBONILLA <STRIOTURBONILLA) ASSHR, new species. 



Plato :i, fii^s. I, \<i. 



Shell elongate-conic, milk-white. Xiiclear whorls small, two, 

 depressed, helicoid, having their axis at right angles to that of the 

 succeeding turns, in the first of which they are about one-third im- 

 mersed. Post-nuclear whorls well rounded, slightly overhanging, 

 ornamented by well developed, somewhat sinuous, rounded, pro- 

 tractive axial ribs, of which there are about 14 upon the third, 16 

 upon the fourth and fifth, 18 upon the sixth to eighth, 20 upon the 

 ninth to eleventh, and 22 upon the twelfth and penultimate turns. 

 Intercostal spaces almost equal to the ribs in width, shallow, ter- 

 minating some little distance posterior to the summit of the suc- 

 ceeding whorl, thus leaving a rather broad, plain band above the 

 suture in each turn. Sutures strongly' constricted. Peripher}^ of 

 the last whorl well rounded. Base short, well rounded. Entire 

 surface of spire and base marked by very fine, closely spaced, spiral 

 striations. Aperture subquadrate. Posterior angle obtuse, outer lip 

 thin, showing the external markings within, columella slender, well 

 curved and slightly re volute. 



The type and a young specimen (Cat. no. 205932, U.S.X.M.) 

 from which the nucleus has been described, come from off Redondo, 

 California. The type has lost the nucleus and first post-nuclear 

 whorl. The thirteen remaining whorls measure: Length, 8.3 mm. ; 

 diameter, 1.9 mm. Two additional specimens (Cat. no. 205933, 

 U.S.N.M.) come from San Pedro, California. Two more (Cat. no. 

 163244, U.S.N.M.) are also from the same locality. 



TURBONILLA (STRIOTURBONILLA; MEXICANA, new species. 

 Plate 3, figs. 5, 5«. 



Shell broadly conic, yellowish-white. Nuclear whorls two and 

 one-half, forming a decidedly elevated helicoid spire, the axis of 

 which is at right angles to that of the succeeding turns, in the first 

 of which it is slightly immersed. Post-nuclear whorls well rounded, 

 appressed at the summit, marked by slender protractive axial ribs, 

 of which 16 occur upon the first and second, 14 upon the third and 

 fourth, and 16 upon the remaining whorls. Intercostal spaces well 

 impressed, at least four times as wide as the ribs, terminating a little 

 distance posterior to the suture, marked by many very fine, closely 

 spaced spiral striations, which do not appear to extend over the 

 ribs. Sutures well impressed. Periphery of the last whorl some- 

 what angulated. Base short, well rounded, marked only by exceed- 

 ingly fine, spiral striations. Aperture large, subquadrate, posterior 

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

 columella slender, slightly curv(Ml and somewhat revolute. 



