72 THE ELEMENTS 



we have not been able to ascertain this 

 point as a fact. 



Habitation. They live in sand at 

 the bottom of the sea; and the animals 

 are provided with a membrane, which 

 they throw over their shells, which 

 preserves the fine polish, and prevents 

 other testaceous bodies from fixing on 

 them. The Cyprsea have only been 

 found to inhabit the ocean. 



In Turton's Linne 120 species of 

 Cypraea are described ; and only one 

 has been found in the British seas. 



Genus 22nd. — BULLA. Animals. 

 Li max ; shell univalve, convolute, and 

 unarmed with teeth ; aperture a little 

 straitened, oblong, longitudinal, very 

 entire at the base ; pillar oblique and 

 smooth. Linn. Sy st. 321. Plate 8th, 

 %. 22nd. 



Habitation. The shells composing 

 the Bulla genus are found to inhabit 

 the ocean, lakes, rivers, and ditches. 

 Those which inhabit the ocean, are 



