( 18 } 



DIVISION XII. CORBULACE^. 



GENERA. 



I 



4. Corbula. Lam. M. F. 



Shell regular, inequi- 1 cardinal tooth on Ligament interior, 

 valved, inequilateral ; not, each valve, conical and fixed in the hollows. (1) 

 or scarcely gaping. Fig. 57. curved; a hollow on the 



side : no lateral teeth. 



2. Pandora. Lam. M. 



Ligament interior. (2) 



3. Productus. Sowerbj-. 

 Foss. 



Equilateral, inequival- Hinge transverse, li- 

 ved, margin reflexed ; the near, 

 one valve convex, the 

 other flat or concave ex- 

 ternally ; frequently fur- 

 nished with spines. Fig. 

 61.62.63. 



Shell regular, inequival- 

 ved, inequilateral, trans- 

 versely oblong; one valve 

 flattened, the other con- 

 vex. Fig. 58. 



2 oblong cardinal 

 teeth, diverging and un- 

 equal, on the flat valve, 

 2 oblong hollows on the 



other. 



(1) Some of these live within stones. M. de Ferussac has a fresh-water spe- 

 cimen in his splendid collection of terrestrial and fluviatic shells. Foss. at 

 Grignon, Bourdtaux, Iialy^ Couriagnon. 



(2) Mediterranean and British Ocean. Foss. in the Limestone Rock, Derbyshire- 

 Peak Rock. 



