MUSSELS AND PECTENS 39 
and light brown without. Diameter five or six 
inches. 
Pécten diegoénsis, Dall, the Diego Pecten, some- 
times known as Pecten floridus, Hinds. This fine 
shell sometimes grows nearly as large as the last 
species, though it is totally distinct. Its two valves 
are unlike, one being nearly flat, while the other 
is moderately arched. Both have very large and 
distinct ribs, twenty or more in number, with deep 
channels between them. The shells vary in color 
from dark red on the flat side to yellow on the 
eurved. <A fine specimen, three inches across was 
given me some years since, by a lady living in Pa- 
cific Grove, who found it alive at low tide. Its 
color is yellow throughout. Fine, large specimens 
have also been dredged at various places. As its 
name indicates, its home is in the south. 
Figure 19 repre- 
sents an exquisite- 
ly beautiful species 
which is essenti- 
ally a northern, 
deep water inhabi- 
tant, though it is 
oceasionally found 
quite far down the 
coast. The shell is 
thin, the ears very 
unequal, and the 
edges of the princi- 
pal ribs are eut in- 
to many short and 
