MAZATLAN BIVALVES 71 



no inconsiderable a portion of the collection.* These shewed 

 great diversities of colouring ; sometimes abounding in the 

 typical dots, sometimes shewing the faintest traces of them. 

 The dots were scarcely ever angulated, according to the de- 

 scription and figures of Sow. The favourite trifurcate white 

 mark at the umbos sometimes darts up long angular rays ; in 

 other cases it is extremely small and irregular. Long. 2*5, 

 lat 2*9, alt. 1*4 

 Hob. Indian ocean, Lamarck. China, Deshayes. [? C. gra- 



phica] Japan, Dr. Sibbald, Mus. Cuming. Mazatlan, very 



rare; L'pool CoL 



Tablet 317 contains 5 young valves, from the Chama and 

 Spondylus washings, the larger of which I think certainly, the 

 rest perhaps, belong to this species. 



Tablet 318 contains 2 adult specimens, one of which at least 

 was from the box. 



GENUS VENUS, Linn. 



Venus, ex parte, Linn., Lam., et auct. 



Chione, Megerle, 1811 ; Gray, 1847 ; Desk. B. M. Cat. Yen, 

 p. 118; (non Gray, 1838.) 



101. VENUS (CHIONE) GNIDIA, Brod. fy Sow. 



Venus gnidia, Zool. Journ. iv. 364. five. Conch. Syst.. pi. 68, 

 f.6?Graym Zool. Beech. Voy. pi. 41, f. 3 . tieless. Rec. 

 de Coq. pi. 19, f. 1, a, I Hani. Descr. Cat. p. 113, pi. 13, 

 f. 43 : Wood's Suppl. pi. 13, f. 43. Sow. Thes. Conch, p. 709, 

 pi. 154, f. 25. B. M. Cat. D'Orb. Moll. p. 68, no. 606. 

 C. B. Ad. Pan. Shells, p. 269, no. 437. 

 Chione gnidia, Desk, in B. M. Cat. Ven. p. 132, no. 41. 



This queen of Veneres nourishes in the greatest luxuriance 

 and magnificence in the Mazatlan seas. Though the texture is 

 not so delicate as that .of Ch. amathusia, nothing can exceed the 

 beauty of the concentric frills, which rise at various intervals 

 generally perpendicular to the surface of the shell. On the 

 back, they carry off the radiating furrows.: on the front they 

 are beautifully crenated. They generally rise into laminae 

 (sometimes '23 long) which are occasionally bent up almost 



* Before I knew how much the species was divided, I distributed under this 

 name in several of the Mazatlan collections (" Hab. incog.") specimens whicfo 

 properly rank under one of the other groups. 



