AET. 22 SAN PEDRO FAUNA— OLDRO YD. 31 



cords, which are successively closer spaced and weaker from the 

 posterior anteriorly, the fourth being really a broad, tumid area, 

 surrounding the umbilical chink. The broad channels separating 

 these cords are crossed by numerous slender axial threads. Aperture 

 oval; posterior angle acute; outer lip thin at the edge, thick within; 

 inner lip curved, reflected over and appressed to the preceding turn, 

 provided with a strong, oblique fold at its insertion; parietal wall 

 covered by a thick callus. 



Tyfe. — Cat. No. 352516, U.S.N.M., has 5 whorls and measures: 

 Length, 3.2 mm. ; diameter, 1.5 mm. 



This is most nearly related to Odostomia {Chrysallida) hetero- 

 cincta Bartsch, from which it is at once distinguished by its more 

 robust size and less acutely tuberculated sculpture. 



Cat. No. 352517, U.S.N.M., contains 2 more specimens from the 

 type locality, and 6 additional specimens are in the Oldroyd col- 

 lection. 



ODOSTOMIA (EVALEA) TERSA, new species. 



Plate 1, fig. 10. 



Shell elongate conic, yellowish white. Nuclear whorls deeply, 

 obliquely immersed in the first of the postnuclear whorls, above 

 which only the tilted edge of the last volution projects. Postnu- 

 clear whorls rather high between summit and suture, slightly 

 rounded, narrowly shouldered at the summit and marked only by 

 lines of growth and very fine spiral striations. Suture slightly con- 

 stricted. Periphery of the last whorl well rounded. Base slightly 

 inflated, rather long, narrowly umbilicated, marked like the spire. 

 Aperture long, oval; posterior angle acute; outer lip thin at the 

 edge, thick within ; inner lip oblique, slightly sinuous, provided with a 

 strong fold opposite the umbilical chink; parietal wall covered by 

 a moderately thick callus. 



Tyjye. — Cat. No. 352518, U.S.N.M., has 5 postnuclear whorls re- 

 maining, having lost probably the first half of the postnuclear turn, 

 and measures : Length, 5 mm. ; diameter, Q mm. 



Cat. No. 352519, U.S.N.M., contains 2 specimens from the type 

 locality, one of which served for description of the nucleus. 

 Four additional specimens are in the Oldroyd collection. 



The present species recalls Odostoviia {Evalea) valdezi Dall and 

 Bartsch, but is more than double the size of that species in every way. 

 The fine spiral striations have been omitted in the figure. 



ODOSTOMIA (EVALEA) ITHEA. new speciei. 



Plate 1, fig. 2. 



Shell regularly broadly conic, yellowish white. Nuclear whorls 

 small, obliquely immersed in the first postnuclear turn, above which 



