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. OSTEEA VIEGINICA, Gmel. 



Gmel. p. 3336, no. 113, teste Dillw. and WoodDilhv. Descr. 



Cat. p. 277 Wood. Ind. Test. p. 52, no. 68. Lam. An. s. 



Vert. vol. vii. p. 225, no. 18. Conr. in Journ. Nat. Sc. Phil. 



1829, p. 212, 216. Sow. Gen. f. 2. 

 Ostrea Virginiana, Gmel. teste Lam. loc. cit. et Gould Inv. 



Mass. 

 Ostrea rostrata maxima, CJiemn. Condi. Cab. vol. viii. p. 38, pi. 



73, f. 677. 



Ostrea elongata, Soland. ms. \-Portl. Cat. p. 55. 

 Sen. = Ostrea crassa, Chemn. loc. cit. p. 40, pi. 74, f. 678. 

 Jun. = Gryphsea 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 Desk. 

 ? + Ostrea longirostris, Lam. loc. cit. p. 243, no. 17, teste 



Trevelyan ; sed v. Desk, in loc. 



? 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 Pacific species, 

 has proved to have come from the Atlantic waters, probably 

 from Honduras. These differ from 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 



