7(3 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Se«. 



Leda alaeformis (Gabb) 



PI. 12. Fig. 12 



Corbula alceformis Gabb, Pal. Gal., vol. 2, p. 177, pi. 29, fig. 

 63. 



The shell is small and thin, rounded anteriorly and narrowed 

 posteriorly; beak forward of the middle, posterior cardinal 

 margin slightly concave, bordered by a broad groove extending 

 from the beaks to the posterior end; basal margin broadly 

 rounded; surface ornamented by fine prominent concentric 

 ribbing. Locality 4, L. S. J. U. Pal. Coll. 



Leda gabbi Conrad 

 PI. 13, Fig. 6 



L. gabbi Conrad, Pal. Gal, vol. 2, p. 197; vol. 1, p. 199, pi. 

 26, fig. 185. 



This species is much more slender than L. alceformis Gabb, 

 and the posterior cardinal margin is usually produced to a point 

 where it joins the broadly convex basal margin; surface marked 

 by many concentric lines, much finer than in L. alcEformis. Lo- 

 cality 4. This species occurs also in the Tejon. L. S. J. U. 

 Pal. Coll. 



Lima perrini Waring 

 PI. 10, Figs. 1, la, and 2 



Lima perrini Waring, Jour, of Geol., vol. 22, No. 8, Nov.- 

 Dec, 1914, p. 782. 



This giant circular Lima has a thick shell with nacreous, and 

 outer prismatic layer ; umbones small ; cardinal margin sloping 

 gradually to posterior where it becomes rounded and grades 

 into the circular margin below ; beaks slightly excavated in 

 front, the margin sloping at a 35-degree angle into the round 

 anterior margin; hinge very thick, with a deep wedge-shaped 

 ligament pit sloping from interior edge of shell to exterior 

 edge at anterior end of hinge line ; a single large sub-posterior 

 muscle impression marking interior of shell ; surface orna- 

 mented by many fine radiating lines, the prismatic shell layer 

 giving the surface a silken appearance. It belongs to the sub- 

 genus Acesta. Locality 4, L. S. J. U. Pal. Coll. 



