100 BULLETIN 68, UNITED STATES NATIONAL MLTSEUM. 



double the width of the ribs, marked by pits and incised spiral lines. 

 Of these the one at the periphery and the one at the anterior termina- 

 tion of the posterior third between the sutures are of equal width, 

 and much wider than the rest; two other pits a little less strong 

 divide the space between the two strong pits into three segments, 

 the middle one of which is a trifle wider than the other two which are 

 equal. The three areas are again divided by finer lines, the first 

 above the periphery being crossed by one, the next by three and the 

 third by two fine striations. The space between the summit and 

 the deep series of pits anterior to it is crossed by four incised and 

 wavy, exceedingly fine spiral lines. Periphery of the last whorl 

 well rounded, marked by the feeble extensions of the axial ribs 

 which disappear shortly after crossing it. Base well rounded, 

 marked by twenty-two well incised subequal and subequally spaced 

 spiral lines. Aperture oval; posterior angle acute; outer lip thin, 

 showing the external sculpture within; columella slender, twisted 

 and slightly re volute. 



The type (Cat. no. 162693, U.S.N.M.) was dredged at U. S. Bureau 

 of Fisheries station 2822 in 21 fathoms, oflF La Paz, Lower California. 

 It has nine post-nuclear whorls and measures: Length 6.7 mm., 

 diameter 1.8 mm. 



TURBONILLA (PYRGISCUS) AURICOMA Dall and Bartsch. 



Plate 9, figs. 5, 5a. 



Turbonilla (Pyrgisais) auricoma Dall and Bartsch, Mem. Cal. Acad. Sci., vol. 3, 

 1903, pp. '274, 275, pi. 1, figs. 4, 4a. 



Shell slender, attenuated, brown, lighter on the early whorls, 

 becoming dark on the last. Nuclear whorls two and one-half, large, 

 helicoid, not immersed, projecting somewhat beyond the outline of 

 the spire, their axis being at a right angle to the axis of the later 

 whorls; post-nuclear whorls at first somewhat rounded, later flattened, 

 marked by well-developed, rather strong, retractive axial ribs, of 

 which 16 appear upon the third and fourth, 18 upon the fifth to eighth, 

 20 upon the ninth, 22 upon the tenth, and 30 upon the penultimate 

 turn. Intercostal spaces a little wider than the ribs on all but the 

 penultimate whorl; on this they are somewhat narrower, crossed be- 

 tween the sutures by nine subequally spaced, almost equally strong, 

 spiral lines of pits, which pass up on the sides of the ribs but do not 

 cross their summit. Periphery and base of last whorl inflated, well 

 rounded, marked by the continuations of the axial ribs, which extend 

 almost undiminished to the umbilical area and eight equally strong 

 and almost equally spaced, well-incised spiral lines. Aperture ovate; 

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

 within, the spiral markings appearing as red threads; columella 



