62 CATECHISM OF CONCHOLOGY. 



the sea ; and the Violet Snail swims at liberty, by 

 means of a cluster of small bladders, which it 

 inflates at pleasure. 



CHAR XXXIII. 



UNIVALVES 

 NERITA; Nerite, or Hoof Shell. 



Q. WHAT are the characteristics of the 

 Nerita ? 



A. A spiral, and gibbous or smooth shell, 

 rather flat underneath ; semi-orbicular (half an en- 

 tire circle), or semi-lunar (half-moon) aperture, 

 having uniformly the pillar lip, or cotumella, 



STRAIT. 



Q. Are not many of these shells extremely 

 beautiful ? 



A. Yes, nothing can exceed the beauty and 

 delicacy of the miniature painting with which 

 many of the Neritse are adorned. 



Q. How are these beautiful colours produced ? 



A. The means of producing them must be 

 sought for in the animals themselves. Their 

 necks are furnished with pores replete with 

 colouring fluid, which blends insensibly with the 



