MAZATLAN BIVALVES 159 
Tablet 702 contains 4 young valves, side denticles not deve- 
loped.—703, an adult specimen, normal shape.—704, do. very 
transverse.—705, do. with very elongated hinge, (from the 
Havre Col.) kindly presented by S. Hanley, Esq. 
212. OsTREA VIRGINICA, Gmel. 
Ginel. p. 3336, no. 113, teste Dillw. and Wood.—Dillw. Deser. 
Cat. p. 277.— Wood. Ind. Test. p.52, no. 68.—Lam. An. s. 
Vert. vol. vii. p. 225, no. 18.—Conr. in Journ. Nat. Se. Phil. 
1829, p. 212, 216.— Sow. Gren. f. 2. 
Ostrea Virginiana, Gimel. teste Lam. loc. cit. et Gould Inv. 
Mass. \ y 
Ostrea rostrata maxima, Gents Conch. Cab. vol. viii. p. 38, pl. 
fog TOL. 
Ostrea elongata, Soland. ms. :— Portl. Cat. p. 55. 
Sen.=Ostrea crassa, Chemn. loc. cit. p. 40, pl. 74, f. 678 
Jun.=Gryphea angulata, Lam. loc. cit. p. 203, no. 1., teste 
Sir W. C. Trevelyan in B. M., non auct. 
+ Ostrea Canadensis, Lam. loc. cit. p. 226, no. 19, teste Desh. 
P+QOstrea longirostris, Lam. loc. cit. p. 248, no. 17, teste 
Trevelyan ; sed v. Desh. in loc. 
P Ostrea sp. ind. d. C. B. Ad. Pan. Shells, p. 246, no. 383. 
Jun. ?=Ostrea rufa (pars), Gould. ms. (California.) 
As the few specimens of this shell sent in the Mazatlan 
collection do not offer any marks by which they can be distin- 
guished from the Atlantic O. Virginica, I have followed Mr. 
Hanley in referring them to that very variable species. So 
like are they, that I have unfortunately distributed many 
specimens in Mazatlan collections, received from a trustworthy 
dealer as from there, which the detection of an entombed 
Mytilus, known to be a W. Indian and not a Pacifie species, 
has proved to have come from the Atlantic waters, probably 
from Honduras. These differfrom the authenticated Mazatlan 
specimens in being generally straighter, shorter, thick, with 
the muscular impression more deeply coloured and lower down: 
but these characters are not constant in either series. C. B. 
Adams remarks of his Ostrea d, which usually occurs in clus- 
ters, that the flavour is superior to that of O. Virginica or O. 
borealis: but the same may be said on comparing varieties of 
O. edulis with each other. The O. Virginica is thus described 
by Gould. “Shell elongated, narrow; beaks pointed, not much 
curved ; ligamentary eminence of the upper valve extending 
back to the apex. This is the common oyster of the Chesapeake 
