CLASS PELECYPODA 
125 
Shell more compressed and thinner than D. orbella, and of a different 
outline. In the description the edge of the excavated hinge plate has 
been mistaken for a lateral tooth. 
Type in Museum Cuming. Type locality, Mazatlan, Mexico. 
Range. Catalina Island, California, to Panama. 
Subgenus Felaniella Dali, 1899. 
Diplodonta sericata Reeve, 1850. 
Conch. Iconica , 6; pi. 9, fig. 55. (As a Lucina.) 
Shell somewhat squarely orbicular, inclined obliquely on the posterior 
side, thin, depressed, concentrically impressly striated, no lunule; semi¬ 
transparent white, covered with a shining pale olive horny epidermis. 
(Reeve.) 
Type in British Museum. Type locality not known. 
Range. San Diego, California, to Panama. 
Family LUCINID2E 
Genus LUCINA Bruguiere, 1797. 
Shell inflated thin, concentrically striated, anterior and posterior dorsal 
areas obsolete; lunule deep and narrow, no visible escutcheon; ligament 
and resilium deeply inset but not occluded; margins entire, anterior 
adductor scar long, hinge wholly edentulous, shell usually large. (Dali.) 
Type. Venus edentnla Linnaeus. 
Distribution. Universal. 
Range in time. Upper Silurian. 
Lucina edentuloides Verrill, 1870. 
Amer. Jour. Sci., 49 \226. 
Closely allied to L. edentnla of the West Indies and the Gulf of Mexico. 
It is subglobose, and much more swollen than L. edentnla. The apex is 
more prominent and curved, and the lunular region more deeply excavated. 
The ligament is shorter and its supporting plate is not so stout, and its 
inner edge but little elevated above the ligament groove. Length, 1.65; 
height, 1.50; breadth, 1.10 inches. (Verrill.) 
Type locality, La Paz, Lower California. 
Range. San Clemente Island, California, to the Gulf of California. 
Genus PHACOIDES Blainville, 1825. 
Shell lentiform, with strong dorsal areas and chiefly concentric sculpture, 
the cardinal teeth obsolete in the adult, but the laterals well developed. 
Type. Tellina pectinata Gmelin. 
Distribution. Universal. 
