22 MAZATLAN BIVALVES 



S. Eleua, D'Orhigny. — Panama, common, C. B. Adams.— 

 Mazatlan ; extremely rare ; L'pool Col. 



Tablet 75 contains 1 specimen, laid open. 



31. COKBULA BIEADIATA, SotC. 



Proc. Zool. Soc. 1833, p. Bo.—MuH. S!/n. Test. Tn\ p. 230.- 

 Bve. Conch. Ic. pi. 1, f. 3.— Hani. Siippl. Wood's Ind. Test. 

 pi. 10. f. bl.—Hanl. Bescr. Cat. p. 47.— -B. M. Cat. B'Orh. 

 Moll. p. 70. no. 620. 



Shell vrith valves nearly equal, ventral margin flattened, 

 posteriorly rather widely overlapping. Epidermis scarcely 

 visible except at tke margin, -vrhere it is, as usual, thick. Within, 

 purplish white, ligament attached to larger tooth. Posterior 

 muscular scar strongly marked, partly projecting, partly indent- 

 ed, subcircidar, Avith the little one behind coalescent. Anterior 

 scar pear-shaped. PaUial line irregular ; sinus very small. 

 Long. -33, lat. -52, alt. '26. 



Sah. — Mud and sand, 3-6 fms., Chiriqui : 7 fm., in Bay of Carae- 

 cas: Cuming. — Ecuador; Chiriqui: UOrhigny. — "W.Columbia, 

 Jay. — Panama, very rare. C. B. Adams. — Gidf of California. 

 Mus. Ciinung.— Mazatlan ; extremely rare : L'pool Col. 



Tablet 76 contains the only specimen found, in extremely 

 fine condition, flattened. 



32. CoEBULA PtrSTXJLOSA, il. s. 



C. t. parvd, alba, ohesa, solidd, postice productd, truncatd, 

 antice rotundatd, ab umhonihus postice subangulatd ; valvd 

 minore plus mhiu^ve Inclausd, maxime in margine ventrali ad 

 jmsticum decurrente, arcuatd : ralvis concentrice liratis, liris 

 irregularibus, suhrotundatis : epidermide tenui, ad marginem 

 crassd : lineis exillimis radiantibiis pustularu m 

 minimarum repletis : umbonib us IcBvigatis. 



Shell small, white, subglobose, produced posteriorly, with 

 tlie valves overlapping, bent at the posterior end of the ventral 

 margm ; with irregular, somewhat roimded concentric ridges, 

 crossed by the finest radiating lines, which mider the microscope 

 are found to consist of rows of minute pustides, probably 

 formed in the epidermis, which is extremely thin over the body 

 of the shell, coarse roimd the margin, and at the posterior side, 

 which is ratlier angidated. 



Mr. Cimiing's specimen measures long. *16, lat. "24, alt. "14, 

 The Mazatlan specimen „ „ 'U, ,, '16, „ "IX, 



