ee eee ee ee ee Oe SG 
H. Gibbons on Springs and Streams in California. 187 
The first, or anterior valve, is externally in the form of an ob- 
tuse V, with four deep narrow fissures at its anterior inner margin. 
The posterior or 8th valve is rounded externally, with a small 
é same color as the mantle, most numerous on the sides and 
resembling shagreen, less numerous on the back, and least of all 
on the convex tubercles. There are also numerous indentations, 
Which are most numerous on the convex portion or back, giving 
it the appearance of haying the granules removed by friction. 
_ The margin is narrow, and, with the whole inferior surface, 
18 coriaceous, : ; 
€ gigantic size of the specimen and the peculiar and unique 
form and structure of its valves render it extremely interesting, 
and a full description and figure of it very desirable and highly 
A ae : 
€ name of gigas at once suggested itself ; but as that name 
already been given to an African species (although one 
much smaller than this), the name of Caljfornicus (from the 
tate upon whose shores it was found) has been adopted. 
It was obtained in California, some 8 or 10 years since, by the 
v. O. C. Baker, of this city, in whose possession it still remains, 
Concord, N, H., March 20, 1863. 
ART. XVIL—On the rising of Springs and Streams in California, 
: before the winter rains; by H. Grssons, M.D., of San Fran- 
Cisco, 
