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 hinge line. 

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



off Chama ; IS pool Col. 



FAMILY NUCUUDJE. 



GENUS JSTUCULA, Lam. 

 Nucula, Lam. 1801. Poly donta, Megerle, 1811. . 



198. NUCULA ? EXIGUA, Sow. 



Proc. Zool. Soc. 1832, p. 198. Mull. Syn. Test. Viv. p. 192. 



Sow. Condi. III. no. 34, pi. 16, f. ZkHanl. Descr. Cat. 



p. 172 B. M. Cat. DOrb. 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 Caraccas, in sandy mud, 9 fm. ; Cuming, D'Orb- 

 igyiy Panama, 1 valve, C. B. Adams. Mazatlan ; 1 valve 

 off Spondylus calcifer ; L'pool Col. 



GENUS LEDA, ScJmm. 



199. LEDA ? ELENENSIS, Sow. 



Nucula Elenensis, Proc. Zool. Soc. 1832, p. 198 Mull. Syn. 

 Test. Viv. p. 191. Sow. Conch. III. no. 19 pi. 15, f. l^.Rve. 

 Conch. Syst. pi. 85, f. U.Hanl. Descr. Cat. p. 169. 

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



Leda Elenensis, B. M. Cat. DOrb. 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. o 



