MOLLUSC A OR UNIVALVES. 171 



angular. They inhabit all parts of the worlds 

 living in dry as well as damp situations. Turton 

 mentions one species as a native of England, 

 C. lapicida, found in the fissures of limestone 

 rocks, and in woods. 



40. Anastoma. — Shell orbicular; spire ob- 

 tuse ; mouth toothed, and turned upwards in 



the adult, nearly reaching the level of the 

 apex. Animal like that of the Helix. — 2 species, 

 recent. 



The structure of this extraordinary shell 

 proves that in completing the last whorl, the 

 animal carries it with the apex downwards, in- 

 stead of its natural position upwards, which is 

 the case with all other shells, and even with 

 itself when young. It is very rare, and is 

 brought from the East Indies. — Only 2 species 

 are known, Anastoma depressa and Anastoma 

 globulosa. 



