120 



DEN TALI UM. 



(Plate XXII. fig. 1.) 



Shell univalve, straight, or nearly so, subconical, 

 tubular, not charnbered, open at both ends. 



The simple construction of the shells in this ge- 

 uus and the paucity of species render it unneces- 

 sary to offer any extended remarks on their di- 

 stinctive character. They are all more or less, as 

 their name expresses, like teeth or tusks, and are 

 completely separated from the other tubular fami- 

 lies by being entirely without contortion, though 

 somewhat curved. 



They are usually discovered partly buried in the 

 sand; and the animal, which has by some naturalists 

 been supposed perfectly free and unattached to his 

 habitation, is seen to shrink deeply into it for pro- 

 tection from impending danger. The opinion, 

 that the Terebella possesses the power of disen- 

 gaging himself from his shell, has arisen probably 

 from the circumstance of there being no apex. 



