WEST AMERICAN PYRAMTDELTJD MOLLUSKS. 31 



TURBONILLA (TURBONILLA i IMA, new species. 



Plate 2, fig. 1. 



Shell laro;e, elono;ate-comc, yellowish-white. (Early whorls eroded.) 

 Those of the post-nuclear whorls remaining are very liigh between 

 the sutures, slightly rounded, feebly shouldered at the summit, and 

 somewhat contracted at the sutures, marked by low, rounded, some- 

 what sinuous, vertical axial ribs, of wliich there are 24 upon the 

 penultimate whorl and 20 upon the second above it. Intercostal 

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

 scarcely depressed below the general surface. The intercostal spaces 

 and ribs between the sutures are marked by rather strong Hnes of 

 growth, which gives them a decidedly crinkly appearance. Sutures 

 well impressed. Periphery and base of the last whorl well rounded, 

 marked by the feeble continuations of the axial ribs. Aperture 

 large; posterior angle acute; outer lip thin, showing the external 

 markings witliin; columella slender, decidedly sinuous, not reflected. 



The type (Cat. no. 123025 U.S.N.M.) has the last eight whorls wliich 

 measure : Length 9.4 mm., diameter 2.2 mm. It was dredged at U. S. 

 Bureau of Fisheries station 3392, in the Gulf of Panama, in 1270 

 fathoms on hard bottom, temperature 36.4°. 



TURBONILLA (TURBONILLA) DIEGENSIS, new species. 

 Plate 2, fig. 13, 13«. 



Shell small, subdiaphanous to dingy white. Nuclear whorls two 

 and one-lialf, helicoid, loosely coiled, decidedly elevated, about one- 

 fifth immersed, having their axis at a right angle to that of the later 

 whorls. Post-nuclear whorls, moderately rounded, somewhat over- 

 hanging, the greatest convexity being on the lower tliird of the 

 exposed portion of the whorls, traversed by 14 broad, coarse and 

 strong, obhque, and somewhat flexuous axial ribs on the fourth 

 and seventh whorl and 18 on the eighth. These ribs extend over 

 the angulated periphery to the umbihcal region, appearing fainter 

 on the base ; the deep intercostal grooves terminate at the periphery, 

 i. e., do not appear on the base as gouged out spaces, as they do pos- 

 terior to the periphery, but simply as plain shallow grooves between 

 the ribs formed by the raising of these above the general surface of 

 the shell. The whorls slope rapidly toward the suture and are some- 

 what contracted and shouldered at the summit, thus marldng a 

 prominent subchanneled suture. Aperture large, broadly ovate, 

 showing the axial ribs witliin; outer lip thin, subpatulous, shortly 

 curved to meet the short, somewhat revolute, sHghtly twisted, colu- 

 mella. 



The type figured has ten post-nuclear whorls, and measures: 

 Length 5.3 mm., diameter 1.7 mm. It comes from San Diego, Cali- 

 fornia, and forms Cat. no. 130316, U.S.N.M. Cat. no. 10916, U.S.N.M., 

 has two specimens from the same locahty, wliile Cat. no. 163217, 



