EOCENE HORIZONS OF CALIFORNIA 783 



160 mm. The umbones are small and the cardinal margin slopes 

 gradually to the posterior where it becomes rounded and grades 

 into the circular margin below. The beaks are slightly excavated 

 in front, and the margin slopes at a 35-degree angle into the rounded 

 anterior margin. The hinge is very thick and has a deep wedge- 

 shaped ligament pit sloping from the interior edge of the shell to 

 the exterior edge at the anterior end of the hinge line. A single 

 large sub-posterior muscle impression marks the interior of the 

 shell. The surface is ornamented by many fine radiating lines, 

 and the prismatic shell layer gives the surface a silken appearance. 

 It belongs to the subgenus Acesta. Leland Stanford Junior 

 University Paleontological Collection. Named in honor of Dr. 

 J. Perrin Smith of Stanford University. 



Pseudoliva reticulata n.sp. — ^Shell subcorneal, whorls four, spire 

 low, suture linear. Altitude 20 mm., width 12 mm. Inner whorls 

 almost covered by body whorl, which is concave. Aperture wide, 

 posterior angular, anterior produced slightly into a canal. Outer 

 lip simple, inner lip incrusted and marked by a fold revolving from 

 the end of the canal around to the inner lip, representing the former 

 positions of the end of the canal. Surface ornamented by longi- 

 tudinal folds and spiral ribs; where these intersect, small tubercles 

 develop. The middle of the body whorl is impressed by a single 

 revolving line which forms a tooth where it is truncated on 

 the outer lip. Leland Stanford Junior University Paleontological 

 Collection. 



Turritella maccreadyi n.sp. — -Shell robust, apical angle broad; 

 whorls eleven, rounded, with six or seven strong, nearly equally 

 spaced, spiral ribs. The first five or six whorls are angulated like 

 T. martinezensis Gb.^ Surface below body whorl also ornamented 

 by spiral lines, and whole surface marked by lines of growth. Aper- 

 ture broad, outer lip slightly sinuous; inner lip sinuous, flattened, 

 and twisted. Leland Stanford Junior University Paleontological 

 Collection. Named in honor of Mr. George McCready of Guan- 

 oco, Venezuela. 



Nautilus hallidayi n.sp. — Shell immense, being about 36 mm. 

 in greatest diameter. The inner whorls are completely enveloped, 



' Geol. Siirv. of California, Paleontology, Vol. II, p. 169, PI. 28, Fig. 51. 



