MOLLUSC A OR UNIVALVES. 175 



These shells are found in almost every part 

 of the worlds from the torrid to the frigid 

 zones ; in the former they attain a large size, 

 and are beautifully coloured, often with lemon, 

 amber, and sea-green, which rarely exist 

 amongst other shells. Many of the species are 

 reversed. They are more commonly found on 

 islands, or on the margin of the sea amongst 

 rocks and trees, than in the interior of the 

 country. The eggs of the Bulimus hcemastoma 

 are large, even sometimes reaching the size of 

 a pigeon's egg, and are represented in the an- 

 nexed fig. 



A specimen of the Bulimus ovalis was once 

 brought from Rio J aneiro, and placed in a hot- 

 house at Chiswick ; it lived for more than a 

 year, and fed principally on lettuces and cab- 



