50 SOLEN. 



The teeth, though differing in the species, are 

 very unhke those of the Telhnse, which most re- 

 semble some individuals of the genus in external 

 characters. 



Specimens of the oval and linear forms are pre- 

 sented in the plate ; but they have not been divided 

 into sections, because there exist intermediate 

 species which it might be difficult to exclude 

 from either. 



The name Solen is derived from cuXriv, a tube. 

 The Latin appellation Unguis, by which this 

 family has sometimes been designated, was pro- 

 bably given on account of the //a//-like or horny 

 substance and colour of many of the species. By 

 the French the shells have been called Manches de 

 Couteaux, in allusion to their shape. 



