GASTEROPODA. 



165 



reflected on the shell; a more or less developed caudal 

 lobe reflected on the spire ; foot large, quadrate, extending 

 beyond the shell posteriorly; gizzard armed with cal- 

 careous plates ; tongue without axile plate, but armed with 

 numerous laterals ; branchial plume single.* — Several 

 species ; also fossil. 



The animal of the Bulla can nearly, but not entirely, 

 enter into its shell ; it swims well by means of the lateral 

 lobes, and is found in the seas of Europe, India, &c. 

 They possess a very singular testaceous apparatus within 

 the body, which acts as the gizzard of a bird, crushing the 

 food, which consists of smaller mollusca with their shells, 

 Sowerby says that they are very voracious, and are some- 

 times distorted by having swallowed entire shells, which 

 are thick, strong, and nearly equal in size to themselves. 

 This apparatus is composed of three bony pieces united 

 by a muscular membrane ; the two side pieces are trian- 

 gular, the other is smaller ; it is sometimes seen shining 

 through the shell. B. ampulla, striata, and some others, 

 belong to this genus. 



Atys. Montf. (Naucum Schum. ; Haminea Gray.) 

 — Shell Bulla-shaped, with the last whorl 

 covering the rest, and hiding the spire, 

 rounded at both ends. Animal, with only 

 a faint intimation of either tentacula or 

 hinder lobes proceeding from the head 

 lobe; the eyes above, like those of Bulla; 

 the foot very large, at the sides parted 

 into two lobes, which are thrown back 

 over the shell, and entirely cover it; a 

 gizzard. — 22 species f ; also fossil. 



* Forbes' s British Moll. f Sowerby's Thes. Conch, 



m 3 



