MAZATLAN BIVALVES 145 



Tablet 666 contains a young valve, '07 across, which may 

 belong to this species. It is however white, with about 30 

 rounded ribs ; inside with a remarkably straight hmge line. 



Hab. — Ecuador, Guayaquil, D'Orbigny, — ? Mazatlan ; 1 valve, 

 oflf Chama ; L'j^ool Col. 



Family NUCULID.^. 



G-ENtJs NUCULA, Lam. 

 Nucula, Lam. 1801.— Polydonta, Megerle, 1811. 



198. Nucula ? exigua, Soio. 



Proc. Zool. Soc. 1832, p. \d^.~Mull. Syn. Test. Viv. p. 192.— 

 Sow. Conch. III. no. 3i, pi. 16, f. 24,.— Maul. Bescr. Cat. 

 p. 172.— -B. 3L Cat. UOrh. Moll. p. 79, no. 704.— C. B. Ad. 

 Pan. Shells, p. 255, no. 'U)Q. 



Tablet 667 contains one very young valve, "03 across, which 

 may belong to this species. The concentric grooves are just 

 forming at the margin. 



Hah. — Bay of Caraccas, in sandy mud, 9 fm. ; Cuming, D'Orh- 

 igny.—Pana.ma,, 1 valve, C. B. Adams.— Mazatlan ; 1 valve 

 off Spondylus calcifer ; L'jwol Col. 



Genus LEDA, Schum. 



199. Leda PElenensis, Sow. 



Nucula Elenensis, Proc. Zool. Soc. 1832, p. \m.—Mm. Syn. 

 Test. Viv. p. \0)\—8o%o. Conch. III. no. 19 pi. 15, f. 14.— -ffj-e. 

 CoTich. Syst. pi. 85, f. 14. — Hani. Bescr. Cat. p. 169.— 

 C. B. Ad. Pan. Shells, p. 254, no. 408. 



Leda Elenensis, B. M. Cat. B'Orb. Moll. p. 63, no. 554. 

 Tablet 668 contains a minute valve, '06 by '04, which may 



belong to this species. Transparent, concentrically grooved, 



but (as in C. B. Adams' specimens) margin not crenulatcd. 



Hah. — St. Elena, in sandy mud, 6 fm. Cuming, B' Orbigny. — 

 Panama, rare, C. B. Adams.— M.aza\\.a-Q. ; 2 valves off Spon- 

 dylus calcifer ; L'pool Col. 



Feb. 1856. 



