the genus cytherea, of lamarck. 303 



Cytherea. 



Shell triangular, solid. Hinder hinge tooth elongated, crenulated. 

 Anterior tooth short, large. Margin entire. Syphonal inflection 

 very slight. 



* Two middle teeth of left valve unequal ; front one longest, 

 bifid. 



Cy. lusoria, Lara. E. M., t. 270, f. 1. 

 Cy. castanea, Lam. E. M., t. 269, f. 1. 

 Cy. zonaria, Lam. Chemn. vi., f. 344. 



** Two middle large teeth of left valve sub-equal, entire. 



Cy. meretrix, Lam. E. M., t. 268, f. 5-6. — the C. petechealis, 

 Lam., does not appear to differ. 

 C. Iriradiata. Chemn. vi., f. 358. 

 C. punguis, Gray, Ann. Phil. 

 C. exilis (Venus exilis, Dillw). 



*** Front middle tooth of the left valve smaller, narrow ; 

 hinder longer. 



C. mitis (Venus mitis, Chemn.) 



C. casta, Lam. 



1 have not seen C. nebulosa, Chemn. vi., f. 359-361. 



Cytherea corpulenta, n. s. — Shell thick, smooth, yellowish. — 

 Umbones white, with zig-zag yellow lines. Hinder slope livid. 



Cytherea sulcata. — Shell trigonal, cordate, rather solid, white, 

 with rather deep, regular, concentric ridges. The hinder slope flat- 

 tened, purple, with small regular ridges. 



Meroe (Schum.) 



Shell ovate, with a deep, impressed, posterior slope. Edge cre- 

 nated. Hinder hinge tooth elongated, crenated. Anterior lateral 

 tooth short, strong. Syphonal inflection moderate. 



Meroe picta (Venus meroe, Linn.) 



Meroe scripla (Donax scripta, Linn.) 



Meroe solandri (Cytherea solandri, Gray ; Venus hynans Solan- 

 der, Wood, Supp., t. 2, f. 11). 



