SCARABI AND OTHER MOLLTJSKS. 411 



enormous vegetable excrescence, or wen growing from 

 the bole of the tree. There are, moreover, covered 

 galleries from the ground, made of mud, leading to the 

 city gates. 



Cuvier says the Scarabi feed on aquatic plants, but I 

 have never observed them among the Algae that lie along 

 the shore; but in the dark, damp woods, more par- 

 ticularly along the sea-coasts, they are very numerous. 

 They love a humid soil, and crawl languidly like the 

 snail. They are fond of congregating together under 

 stones and tree-roots, or in holes of the ground. They 

 feed on partially decayed leaves, and lay their eggs under 

 damp rotten logs, and the young shells may be found 

 concealed, in large numbers, in the crevices of dead 

 trunks. The Scarabi assume various shades of colour, 

 from a mottled reddish brown to pale yellow, and I have 

 even seen them white. 



The species of Conovulus, which lives entirely in the 

 salt water, has a shell of a much firmer character than 

 that which is found amphibious, among the mangrove 

 swamps. In fact, it generally follows, that shells, which 

 inhabit both the land and the water, are intermediate in 

 density of structure between marine and terrestrial species, 

 and are covered in general with an epidermis. Thus we 

 find Telescopium, Potomis, and Terebralia, covered with a 

 kind of epidermis, and their calcareous dwellings less 

 solid than their marine analogues, the Ccrithia. In like 

 manner, I have found a shell in the rivers of Celebes, 

 named Mdatoma, by Swainson, which bears the same 

 relation to PIcuroloma. The Potawomya is a thinner 



