138 INTEODUCTION TO CONCHOLOGY. 



tubercles are prolonged into a lofty diadem of vaulted 

 spines. The Scalaria produces a unique effect, by a perio- 

 dical deposit of the reflected margin of the aperture, caus- 

 ing the whorl to become encircled with numerous rings. 

 Lastly, the PJiorus possesses the remarkable property of 

 attaching to his thin shell, by means of a glutinous exuda- 

 tion, the various pieces of corals, shells, or stones with 

 which he comes in contact. Each species shows a different 

 modification of this pecuHarity, which seems in accordance 

 with tlie fragile nature of the shell. 



TurUnacea chiefly inhabit the Eastern world. 



Such mollusks as pertain to the first genus, Turritella, 

 are apparently a strong and muscular group, the disc being 

 surmounted by a stout pedicle, which upholds the shell and 

 prevents it from trailing upon the ground. A peculiarity 

 is also obvious in the mantle, which is prolonged into a 

 fringed ring, or collar, through wliich the head passes in 

 and out of the shell. 



Although inhabiting alike the East and West Indies, 

 and occurring occasionally on the coast of Senegal and 

 New Holland, Tmntellce present none of those brilliant tints 

 which attract the attention of naturalists, and are generally 

 indicative of sunny climes. The shells exhibit little variety 



