MAZATLAN BIVALVES 69 



97. DlONE ? BEEVISPINOSA, Sow. 



Cytherea brevispinosa, Soiu. Thes. Conch, p. 632, pi. 132, f. 109. 

 Dione brevispinata, Desk, in B. M. Cat. Ven. p. 76, no. 70. 



Tablet 314 contains a minute valve which may be the young 

 of this species. It has close concentric rounded ribs, and very 

 strong teeth for the size. Length "03. 



Hob. Gulf of California, Col. Cuming. ? Mazatlan, jun. 

 1 valve ; Lpool Col. 



98. DIONE CIKCINATA, Born. 



Venus circinata, Born, Test. Mus. p. 61, pi. 4, f. 8. Chemn. 



Conch. Cab. vi. 312, pi. 30, f. 3Il.Dillw. Eec. Sk. i. 169. 



B. M. Cat. Sagr. Moll. p. 39, no. 474. 

 Cytherea circinata, Sow. Thes. Conch, p. 631, pi. 132, f. 104-6. 



Forbes Hani. Br. Mol. i. 399. 

 Dione circinata, Desk. B. M. Cat, Ven. p. 77, no. 72. 

 Venus Guineensis, G-mel. Syst. Nat. p. 3270, &c. 

 Cytherea Guineensis, Lam. An. s. Vert. ed. Desk. vi. 311, &c. 

 Cytherea alternata, Brod. Proc. Zool. Soc. 1835, p. 45. 



Tablet 315 contains a small white valve which may be the 

 young of this species : long. "08, lot. '095, alt. "05. 

 Hal). Cuba, Sagra. S. Atlantic, Forbes. Mazatlan, Capt. 



Donnel : do. Lieut. Grreen, (Gould ms.) : do. one valve and 



fragments, jun., Lpool Col. Var. alternata, Monte Christi, 



in sandy mud, 11 fm., Cuming. 



99. DIONE CONCINNA, Sow. 



Cytherea concinna, Proc. Zool. Soc. 1835, p. 23. Sow. Thes. 



Conch, p. 630, pi. 132, f. 99, 100. 

 Dione concinna, Desh. B. M. Cat. Ven, p. 74, no. 61. 

 Comp. D. affinis, Brod. Proc. Zool. Soc. 1835, p. 45 ; B M. 



Cat. Ven. no. 60 : and D. tortuosa, Brod. id. ; B. M. Cat. 



Ven. no. 62. 



This shell is coloured in sienna brown and white stripes in 

 about equal proportions, the brown being darker on the ribs 

 and in the lunule. Umbos yellow. Concentric ribs occasionally 

 bifurcating. Pallial sinus, long, narrow, ascending. Long. 1*2, 

 lat. 1'56, alt. '75. 

 JIab. Panama, in fine sand, 10 fm. Cuming. Mazatlan ; 1 sp, 



with D. rosea ; Lpool Col. 



Tablet 316 contains the specimen. 



