408 MOLLUSCA. 



Castalia, Lam., 



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

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

 them some affinity with the Trigoni3e(l). 



There are certain Marine Mollusca which 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, Brug.(2) 



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

 some, gaping(3). 



CypricardiAj Lara. 



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

 three. Their form is oblong, and their sides unequal(4). 

 M. de Blainville also separates the 



CoRALLiopHAGAj Blainv.j 



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(5). The 



VenericardiAj Lam. 



Only differ from the Carditse, in the circumstance that the pos- 

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

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



(1) Castalia ambigua, ham., Blainv., Make, LXA^I, 4. 



(2) Chama antiquata, Chemn., VI, xlvii,488 491; Ch. trapezia, Ch. semior- 

 bimlata; Ch- cordaia,ld., 502, 503; and among the fossil species, one of the most 

 singular, Cardita avicularia, Lam., Ann. du Mus., IX, pLix, f. 6, provided it should 

 not be separated. 



(3) Chama caliculata, Chemn., VII, i, 500, 501; Cardita crassicosta, Brug., En- 

 cyc. pi. 234, f. 3. 



(4) Chama oblonga, Gm., Chemn., VII, 1, 504, 505, or Cardita carinata, Encyc, 

 pi. 234, f. 2, or Cypricardede Guinee, Blainv., Malac, LXV, bis, f. 6. 



(5) Chama coralliophaga, Gm., Chemn., X, clxii, 1673, 1674, or Cardita dacty- 

 lus, Brug., Encyc, pi. 234, f. 5; Coralliophaga carditoides, Blainv., Malac, 

 LXXVI, 3. 



