9(i 



MOLLUSCA. 



Castalia, Lam., 



Where the slightly codiform shell is striated in radii ; the teeth 

 and plates of the hinge arc transversely sulcated, which gives them 

 some affinity Avith the Trigonioe *. 



There are certain Marine Mollusca wliich have a similar animal, 

 and about the same kind of hinge, that should be placed near the 

 Unios ; the summits of the shell, however, are more convex, and it is 

 marked by projecting ribs extending from the summits to the edge. 

 They form the 



Cardita, Briig.f 



Which are more or less oblong or codiform, the inferior margin, in 

 some, gapingj. 



Cypricardia, La?n. 



Carditse, in which the tooth under the summit is divided into two or 

 three. Their form is oblong, and their sides unequal §. 

 M. de Blainville also separates the 



CORALLIOPHAGA, BlaiilV., 



Where the shell is thin, and the lateral plate considerably effaced, 

 which may cause their approximation to Venus. 



One of them is known which excavates coralline masses to form 

 its habitation ||. The 



Venericardia, Lam. 



Only differ from the Carditae, in the circnmstance that the pos- 

 terior plate of their hinge is shorter and more transverse, which 

 caused their approximation to Venus; their form is almost round. 

 Judging from the impressions of its muscles on them, their animal 

 must resemble that of the Carditse and Unios.^ 



Both of them approach the Cardia in their general form and the 

 direction oi their ribs. I suspect that this is also the place for the 



Crassatella, Lam , — Paphia, Roiss., 

 Which has sometimes been approximated to Mactra, and at others 



* Castalia ambigua, Lam., Blainv., Malac, LXVII, 4. 



t Chama antiqnccia, Chemn., VI, xlvii, 488 — 491 ; — Ch. trapezia; — Ch. semior- 

 IjicuJata ; — Ch. cordafa. Id., 502, ."ioa ; and among the fossil species, one of the most 

 singular, Cardita avicidaria, Lam., Ann. du Mus., IX, pi. ix, f. 6, provided it should 

 not be separated. 



X Cltiima caliculata, Chemn., VII, i, 500, 501 ; — Cardita crassicosta, Brug., Encyc. 

 pi. 234, f. 3. 



§ Chama oblonga, Gm., Chemn., VII, 1, 504, 505, or Cardita ccrinafa, Encyc., 

 pi. 234, f. 2, or Cijfricarde de Guinie, Blainv., Malac, LXV, bis, f. 6. 



II Chama coraliiophaga, Gm., Chemn., X, clxii, 1C73, 1674, or Cardita dactylns, 

 Brug., Encyc,, pi. 234, f. 5 ; — Coralliophaga carditoides, Blainv., Malac, LXXVI, 3. 



^ Venus imbricata, Chemn., VI, xxx, 314, 315, and the fossil species. Lam., 

 Ann. du Mus., VII, and IX, pi. xxxi and xxxii. 



