MAZATLAN BIVALVES 43 
anterior side much elongated. Long. 1°52, (ad sinum 1°37,) 
lat. 2°28, alt. ‘9, (ad sinum °78.) 
Hab:—Mazatlan ; extremely rare; L’pool Col. 
Tablet 137 contains the only specimen I found: Mr. White- 
head of Liverpool found another. : 
Genus DONAX, Linn.* 
71. Donax carinatus, Hanl. 
Proc. Zool. Soc., 1843, p.5.—Rve. Conch. Icon. pl. 2, sp. 11.— 
Wood's Suppl. pl. 14, f. 28. 
Shell with a blunt keel, and posterior area covered with 
slightly expressed strize which are scarcely rugose here and 
there. Epidermis very thin, deciduous except round the mar- 
gin. Ventral margin almost always regularly excurved. The 
purple colour generally predominates in this, as the chesnut 
in D. culminatus. Form and markings very constant, except, 
as usual, in the proportion of length and breadth. Long. °93, 
lat. 1°62, alt. °63. 
Hab.—San Blas, Gulf of California, Reeve.-—Tumaco, Hinds, 
B. M.—Mazatlan ; rare; L’pool Col. 
Tablet 138 contains 2 specimens in the normal state, and one 
with two remarkable lamine in the interior of one valve, near 
the posterior adductor. 
72. DoNAX CULMINATUS, ?1..s. 
D. carinatus, var: Hanl. ms. teste Cuming. 
D.t.“ D. carinato” simili, sed cariné multo acutiore, producta, 
margine ventrali sepe prope carinam paulum incurvato ; niten- 
tiore ; striis radiantibus obsoletis et crenulatione interna convent- 
ente crebrioribus ; ared posticd striis radiantibus creberrimis 
valdeextantibus, granosis, granis versus marginem rugosis ; 
castaneo-purpureo. 
Thad passed this shell over as the young of D. carinatus, till I 
obtained a number of large valves with other West Coast shells, 
which at once displayed the remarkable characters of the 
posterior area, the sharp ridge, and the very granular crowded 
strie. Having examined more than 60.specimens of D. carin- 
* The specific termination being given as feminine in P. Z. S., B. M. Cat. 
D’ Orb. Moll., Rve. Conch. Icon., Jay’s Cat. &c., it is desirable to remember that 
Donax is masculine both in Latin and Greek: (v, Lex.) In quoting, the termin- 
ations are altered accordingly. 
