40 CONCHOLOGY. 



C. Australis. The Australian Corbula. 

 Irregular species, living in stone. 



2. Pandora. Two species. 

 Closely allied to the Corbula. 

 Pandora rostrata. Pandora obtusa. 



P. rostrata. The beaked Pandora. PI. 6, fig, 3. 



Shell white, regular, elongated, inequivalve, inequilateral ; 

 right or upper valve entirely flat, with a plait or fold ; much 

 produced towards the beak ; hinge anomalous, formed by a 

 transverse cardinal tooth on the right valve, entering into a 

 corresponding cavity on the left ; ligament internal, oblique, 

 triangular, inserted in a pit rather deep, with edges a little pro- 

 jecting on each valve ; two rounded muscular impressions. 



FAMILY VII. 

 LiTHOPHAGi. Three genera. 



1. Saxicava. Five species. 

 This genus is taken from the Mytilus, and, like the Pholas, 

 possesses the faculty of penetrating calcareous rocks, from 

 which it cannot be extracted without breaking the substance 

 in which it is imbedded. 



Shell bivalve, thick, covered with epidermis, rather ir- 

 regular, elongated, sub-cylindrical, obtuse at the two ex- 

 tremities ; summits little marked ; hinge toothless, or with a 

 very small rudimentary tooth : ligament external, a little in- 

 flated. 



Saxicava rugosa. Saxicava pholadis. 



S. Gallicana. S. Australis. 



S. veneriformis. 



S. Australis. The Australian Saxicava. PL 7, fig. 6. 

 Answers to the above description. 



S. Gallicana. The Gallic Saxicava. 

 Oblong, wrinkled, truncated at the posterior extremity, 

 one valve larger than the other ; pale horn colour. 



