TERTIARY FOSSILS. 29 



than any previously known. Two other species, both living on the Pacific coast, 

 may also be included in the sub-genus; viz., L. excavata, Carpenter, Mazatlan 

 Catalogue, p. 98, and a small subglobose species, with five or six large, rounded, 

 somewhat curved ribs ; found in the Gulf of California. 



L. (H.) RlCHTHOFENI, D. S. 

 PI. 8, Fig. 49, a, b. 



Shell subglobose, nearly equilateral; beaks small, inclined 

 forwards; margins regularly rounded; a more or less distinctly 

 marked groove passes from the beaks to the posterior margin. 

 Surface marked by numerous, more or less regular, distinct, 

 rounded ribs. 



Figure 49, magnified ; 49 a, natural size, view of anterior end ; 49 b, magnified 

 view of the hinge, left valve. 



Locality: San Fernando Valley, north of Los Angeles; Pliocene. Collected 

 by Baron Richthofen. 



This species can be at once distinguished by its thick shell and nearly globular 

 form, from all of the other California Lucinidce. Externally, it is almost identical 

 with L. Domingensis in some of its varieties. 



CRASSATELLA, Lam. 



C. COLLINA. 



PI. 8, Fig. 50. 

 v ' . collina, Con. ; Pacific R. R. Rep., V. 7, p. 193, pl. 6, fig. 1, 2.) 



Shell large, compressed, variably subtriangular; beaks a little 

 in advance of the centre; prominent; anterior end broadly and 

 very slightly excavated above, prominent and rounded below; 

 posterior end sloping sinuously, subangular below ; base deeply 

 convex ; surface marked by irregular lines of growth ; lunule 

 deeply impressed ; hinge robust. 



Figure, natural size. 



Locality and position : Miocene, from the Santa Inez Mountains. 



The figure in the Pacific Railroad Report is scarcely recognizable, but with the 



