' ( 5 ) 



4. Saxicava Bellevue. M. 



Transverse, inequilate- Hinge with only 2 

 ral, gaping at the upper dentiform tuberosities, 



part. Fig. 3, 



5. Venerirupis. (Vene- 

 rupis. Lam.) M. 



Inequilateral, gaping at 

 one end. Fig. 4. 



wide apart. 



Hinge with 2 teeth on 

 one valve, and 3 on the 

 other, or 3 on each, 

 small, near together, and 

 parallel. 



Ligament exterior 



Ligament exterior. 



DIVISION III. SOLENACEiE; 



1. Solen. Lin. M. 



Equivalved, transverse- 

 ly elongated ; gaping at 

 each end, sometimes a little 

 curved. Beaks very small, 

 not projecting. Fig. 6. 



GENERA. 



Hinge lateral, with 2 

 or 3 little teeth, joining 

 each other laterally 

 when shut. 



Ligament exterku 



«. Cardinal teeth contiguous to the anterior edge. 



/?. . . . . distant from 



y. . . £. nearly in the middle. (1) 



2.SANGUINOLARIA.Z/«m.M. 



Sub-elliptic, gaping a 

 little at the lateral extre- 

 mities, upper edge arched. 

 Fig. 8. 



3. Glycimeris. Lam. M. 



Shell gaping widely on 

 each side : the second 

 edges * (interior and cal- 

 lous) projecting without. 

 Fig. 7. 



2 contiguous cardinal 

 teeth on each valve. 



Ligament exterior. (2) 



Hinge callous, 

 teeth. 



no 



Ligament exterior, on 

 the shortest side of the 

 shell. (3) 



(1) They live in the sand on the sea-shore, and bury themselves even two feet 

 below the surface, in a vertical position ; consequently, when the animal is living, 

 the shell is always placed perpendicularly on one of its sides, the gaping part 

 uppermost Cor the passage of its. tubes. Its movements are confined to leaving the 

 bottom of its hole, coming to the surface, and re-entering by means of the exten- 

 sions and contractions of its muscular foot, which is at the lowest end of the shell. 

 Foss. at Grignon, Bourdcaux , //a/y, and in the London Clay. 



(2) Jamaica, New Holland, American and Indian Sea9. Foss, in the London 

 Clay. 



' ApudGallos, Nymplioe. v. Fig. 30. a. 



(3) Northern Seas. Foss. at Grignon, 



