354 INTHODUCTION TO CONCHOLOGY. 



a small^ curved, testaceous appendage, situated before the 

 spoon-shaped process, and, being connected with the liga- 

 ment, serving to strengthen it. We ma}^, therefore, assume 

 that the Anatina, though burrowing in sand, is occasionally 

 exposed to the rough beating of a boisterous sea. 



The genus Thracia is characterized by an oval, oblong, 

 and inequivalve shell; thin, fragile, and gaping at both 

 sides. The liinge consists of a more or less prominent, 

 horizontal, concave tooth in each valve, receiving the liga- 

 ment ; and the pallial impression is deeply marked. 



Shells of Corhula are remarkable for their solidity, and 

 peculiarity of growth ; and the two valves present a greater 

 inequality of size and general sculpture than those of any 

 other mollusks of the class. They are mostly marine, al- 

 though a few, like the CeritJda, are found in fre&h or 

 brackish water. Lamarck mentioned only eight species. Mr. 

 Cuming added to them seven new ones, discovered along 

 the western coasts of South America ; and about twice that 

 number have been described by Mr. Hinds, from collections 

 made by himself, in company with Captain Belclier, and by 

 Mr. Cuming, during his researches amongst the Philippines. 



The Red-toothed Corhula [C. erythrodon) may be easily 

 recognized by the rich marginal painting of the interior. 



