MOLLUSCA OR UNIVALVES. 



191 



clusters attached to sticks or other things in 

 the water; when dry, they have a beautiful 

 appearance. 



M. Quoy has proposed to form two species 

 of Lamarck's genus Ampullaria into a distinct 

 genus, which he calls Ampullacera. The ani- 

 mal is totally different, though the shells 

 greatly resemble each other. 



58. Ampullacera (Quoy). — Shell rather 

 thick, globular ; mouth round or oblique, hav- 

 ing the lips united ; spire short ; 

 umbilicus very deep ; operculum 

 horny, thin, and having some- 

 times a projection. Animal, head 

 large, flat, divided into two lobes, 

 and having two sessile eyes ; no appearance 

 of tentacula; foot short and square. — 2 species 

 recent. 



This mollusc is found in great abundance in 

 New Zealand, living in pools of brackish water, 

 and buried in sandy mud. It is eaten by the 

 natives. When the animal is touched it enters 

 very deeply into its shell, at all times is much 

 hidden by it, and sometimes even fills the en- 

 trance with earth. 



