MOLLTJSCA. 151 



mace- 'sal secrets, and if it have any advantage 

 over most of the others, it is that it contains 

 nothing hurtful or poisonous. 



M. Mylius, unaware of the discovery of Jacobson 

 mentioned above, has found uric acid in H. pomatia 

 immediately between the shell and the animal, 

 whence it can be extracted by water. By shaking 

 the snail in water, the uric acid is separated, and 

 soon deposits itself, as an insoluble powder, at the 

 bottom of the mucilaginous liquid thus produced. 



Among sea snails, the common Periwinkle 

 (Turbo littoreus), one of the most common Mollusca 

 in our latitudes, and small Whelks (Buccinuni), 

 which are eaten with a pin, together with several 

 of their allies, are extensively used as food. The 

 heaps of periwinkle shells that are seen at the out- 

 skirts of fishing villages on the coasts of England, 

 Belgium, etc., suggest that some use ought to be 

 made of them. In soils which are deficient of lime, 

 these shells might be coarsely powdered, and spread 

 over the ground. 



A species of Haliotis, sometimes called the Ear- 

 shell, a large, handsome Gasteropod, whose shells, 

 when polished, present the most varied and magni- 

 ficent tints, with mother-of-pearl lustre, and which 

 are easily recognized by the circular holes perfo- 

 rated along the edges of the shell, is frequently 

 seen in the shops for sale as an ornament. 



