54 GENUS V. SOLEN. 



or umbo is in general small and flat ; it is always close to the 

 cartilage, whether that be near to the centre or to one end. 



There are a few shells placed here by Linnaeus, and more 

 by Gmelin and Turton, which would evidently be better re- 

 moved, as Solen sangmnoleiitus, bidlatns, anathms, &c., since 

 the teeth do not agree with the generic definition. 



Linnaeus has described 11 species, Gmelin has added 13, 

 and Dr. Turton none. In all, 23. 



Lamarck has divided this genus into two, as follows : 

 Sanguinolaria. Shell transverse, the upper edge arched, a 

 little gaping at the extremities ; the hinge teeth two, 

 approximating and articulating on each valve (see Solen 

 sangwinolentus, jtl. 2. /. 14). 

 Solen. Shell transverse, the upper and lower edges nearly 

 straight ; beaks not projecting, gaping at both ends ; 

 hinge teeth single in each valve, or double in one ; carti- 

 lage external (see Soleti Vagina, pi. 2. /. 13). 



