FAMILY 4. MYARIA. 51 



adopting the genus Thraria. We also include his family of Corbulacea 

 with the Myaria ; and, in addition to these, are happy to have the op- 

 portunity of introducing three new and interesting genera from later 

 writers, making eight in all, as follows : 



Mya. Pandora. 



Anatina. Anatinella. 



Thracia. Myochama. 



corbula. cleidoth/erus. 



MYA, Linnaeus. 



Testa transversa, imequilateralis, utroque latere hians. Dens cardinalis 

 in valva altera unicus, magnus, cochleariformis, dilatato-compressus ; 

 fovea edentula in altera. Impressio muscularis pallii sinu magno. 

 Ligamentum internum, inter dentem foveamque insertum, 



The genus Mya, which serves to connect this family with the Solenacea, 

 though not very numerous in species, is peculiarly characterized. Its 

 shell is transverse, inequilateral, gaping at both ends, and covered with 

 a thick epidermis, which is continued at the anterior extremity over two 

 lobes, protruded by the animal in making its way in the sand. There is 

 a large, prominent, spoon-shaped tooth in one valve, with a corresponding 

 pit or cavity in the other, between which the ligament or cartilage is in- 

 serted. The muscular impression of the mantle is very distinct, and 

 exhibits a large sinus. 



Example. 



PL XXXIII. Fig. 1 and 2. 



Mya arenaria, Linnaeus, Syst. Nat., p. 1112. Enc. Meth., vol. ii. 

 p. 592. pi. 229. f. 1. 



h2 



