NEW FOSSIL MOLLUSCA OF CALIFORNIA. 337 



EXPLANATION OF PLATES. 



Plate XL VII. 



Pigs. 1 aud 2. Sistrum cretaceum u. sp. 

 Figs. 3 and 4. Littorina siibobesa n. sj>. 

 Fig. 5. Calliostoma lignitica n. sp. 

 Fig. 6. Sigaretus costatus u. sp. 

 Figs. 7, 8 aud 9. Opis triangulata Cooper. 



Plate XLVIII. 



Fig. 10. Cardita alticosta Gabb. 



Figs. 11 and 12. Pholadomya (Triplicosta) progressiva n. subgen. 

 and n, sp. 



Note. — The figs, of pi. xlvii, with the exception of No. 7, twice the 

 natural size; those of pi. xlviii, natural size. 



