ODER BIVALVE -MOLEUSKS 87 
Semele rubro-picta, Dall, the Rose-painted Se- 
mele, is thick, convex, white, with rose rays out- 
side, and marked with heavy, interrupted, concen- 
trie ridges and obsolete radial striation. Inside 
it is white or yellow, never purple. The surface is 
not granular. This is a southern species, found 
near San Diego. It is very probable that there are 
other species of this difficult genus, that are not 
vet deseribed. 
Cumingia californica, Conr., 
the California Cuming-shell, 
igure 78. It is somewhat tri- 
angular in outline, with the 
front rounded and the rear end 
narrower and slightly twisted. 
The lines of growth are very 
distinct, forming concentric ridges. The shape of 
the shell varies considerably in different speci- 
mens. Pallial sinus large, color white, length about 
an inch. From Monterey southward. 
Coopereélla subdiaphana, Cpr., the White Cooper- 
shell, (GEdalia s.). This species has a thin, white, 
glistening shell, which appears quite swollen. The 
hinge-teeth are central, and the short ligament is 
situated almost between the prominent beaks. 
Length half an inch; southern. 
Cooperélla scintilleformis, Cpr., the thin Cooper- 
shell, is another southern species. It has a very 
thin shell, about half an inch long, but less swollen 
than the last. 
Corbula lutéola, Cpr., the Yellow Basket-shell, 
is shaped somewhat like a small Donax, and is well 
