22 WEST AMERICAN SHELLS 
shell is compressed and of a dark chestnut brown 
color. The specimen was obtained by dredging 
near Catalina Island, in about 300 feet of water. 
Another species, considerably larger than the 
last, but not quite so long as the figure, is Leda 
taphria, Dall, the Grooved Leda. The name is 
taken from the Greek, and means, ‘‘full of ditches 
or furrows.’’ The shell is as round as a fat bean. 
There are more grooves on the sides than in Fig. 
9, as might be expected from the name, but the 
narrow end of the shell is much shorter. The 
specimens in my cabinet were obtained from San 
Pedro Bay. 
The genus Yoldia resembles Leda in some 
respects, but the shells are generally larger and the 
posterior end is not so prolonged or distinctly 
marked. The hinge-teeth are V-shaped and nu- 
merous, sometimes numbering 20 or more on a 
side. There are a good many species found along 
our coast, but most of them live at a considerable 
depth, or in the cold waters of the north. 
The largest of the 
Pi ‘ species is named Yol- 
by), dia codperi, Gabb, Coop- 
Dy r’s Yoldia, and some- 
times it grows to a 
length of two or three 
Big.) 10g inches. The shell is thin 
and compressed, while the hinge-teeth are very 
numerous, there being about 12 in front and 40 
or 50 behind. The surface has distinct concentric 
ridges. It is found fossil at San Pedro, and living 
off the coast of central California. Figure 10. 
