lO 
Plate 27. 
Page 
igure 1. Modiolus demissus Dillwyn. 70 
Exterior of left valve. 
2. Mytilus californianus Conrad. 66 
Exterior of left valve. 
3. Lyonsia califoniica Conrad. 91 
4. Mytilus cdulis Linnaeus. 66 
Exterior of left valve. 
. Botula californiensis Philippi. 71 
This plate from University of California Publ. 
Vol. 14, Zoology, Packard. 
