MAZATLAN BIVALVES 145 
Tablet 666 contains a young valve, ‘O07 across, which may 
belong to this species. It is however white, with about 30 
rounded ribs ; inside with a remarkably str aight hinge line. 
Hab.—Ecuador, Guayaquil, D’ Orbigny.—? Mazatlan ; 1 valve. 
off Chama; L’pool Col. 
Famity NUCULID/. 
Genus NUCULA, Lam. 
~ Nucula, Lam. 1801.—Polydonta, Megerle, 1811. 
198. NucuLa P Exiaua, Sow. 
Proc. Zool. Soc. 1832, p. 198.— Mill. Syn. Test. Viv. p. 192.— 
Sow. Conch. Ill. no. 34, pl. 16, f. 24.—Hanl. Deser. Cat. 
p. 172.—B. M. Cat. D’ Orb. Moll. p. 79, no. 704.—C. B. Ad. 
Pan. Shells, p. 255, no. 409. 
Tablet 667 contains one very young valve, ‘03 across, which 
may belong to this species. The concentric grooves are just 
forming at the margin. 
Hab.—Bay of Caraceas, in sandy mud, 9 fm. ; Cuming, D’ Orb- 
igny.—Panama, 1 valve, C. B. Adams. —Mazatlan ; 1 valve 
off Spondylus calcifer ; E ‘pool Col. 
Genus LEDA, Schum. 
199. Lepa ? ELenensts, Sow. 
Nucula Elenensis, Proc. Zool. Soc. 1832, p. 198.—Mull. Syn. 
Test. Viv. p. 191.—Sow. Conch. Lil. no. 19 pl. 15, f. 14.—Rve. 
Conch. Syst. pl. 85, f. 14. — Hanl. Deser. Cat. p. 169.— 
C. B. Ad. Pan. Shells, p. 254, no. 408. 
Leda Elenensis, B. IZ. Cat. D’ 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 crenulated. 
Hab.—St. Elena, in sandy mud, 6 fm. Cuming, D’ Orbigny.— 
Panama, rare, C. B. Adams.—Mazatlan ; 2 valves off Spon- 
dylus calcifer ; L’pool Col. 
Feb. 1856. : 0 
