( 9 ) 



■ 



3. Cyrena. Lam. F. 



. Rounded, triangular, 3 teeth on each valve, Ligament exterior, on 

 swelled or ventricose, so- generally two lateral the largest side. (1) 

 lid, inequilateral; with an teeth, one of which is 

 epidermis, but the beaks often close to the car- 

 naked. Fig. 23. dinal teeth. 



a. Lateral teeth dentated. 

 j?. . . . . entire. 



4. Capsa, Lam. M. 

 Equivalved. Fig. 24. 



2 cardinal teeth on Ligament exterior, on 

 the right valve, 1 bifid the shortest side. (2) 

 entering tooth on the 

 other. No lateral teeth. 



5. Loripes. Poli. M. 

 Lenticular. (3) Fig. 37. 



Cardinal teeth almost 

 effaced. 



Ligament exterior, in 

 a simple furrow. Be- 

 sides the usual impres- 

 sion, a line from that of 

 the anterior muscle to- 

 wards the beaks. 



6. LuciKA. Brug. M. 



Sub-orbicular, inequi- 2 diverging cardinal Ligament exterior, the 

 lateral; beaks small, point- teeth, 1 bifid, all vary- muscular impressions 

 ed j oblique. Fig. 25. ing or disappearing with (one of which is pro- 

 age ; 2 lateral teeth (1 longed into a streak) 

 close to the cardinal) or very wide apart. (4) 

 none. 



7. Corbis. Cuv. M. 



Equivalved, without 2 cardinal and 2 late- Ligament exterior, 



fold or anterior edge, ral teeth. muscular impressions 



beaks curved within, op- simple. (5) 

 posed. Fig. 26. 



(1) There are none found in. Europe. Fluviatic and Marine Conchae differ not 

 only in habitation, but in lateral teeth. 



(2) From Brazil and the Indian Ocean. 



(3) Lamarck only sees a specific difference in these shells, adopted as a genus by 

 Poli and Cuvier. 



(4) Foss. Grignon, environs of Paris, Chaumont, Longjumeau. 



(5) Indian Ocean. The fossil species of this genus are very flat. Foss. at 

 Gngnon, Marl-pits of Granville. 



i 



