MOLLUSCA OR UNIVALVES. 167 



that they formed a portion of the food of the 

 Israelites both in the desert and on their way 

 to the Red Sea, the country in that neighbour- 

 hood being described by travellers as having a 

 herbage under the trees completely covered 

 with snails of a large size. They form in 

 some countries, as Switzerland, Britany, and 

 some parts of Germany, a considerable article 

 of commerce. They are fed by thousands in 

 places made on purpose for them. It is sup- 

 posed the Romans also fattened the Helix 

 pomatia in the same manner. Even at the 

 present day the Helix aspersa is sold in Covent 

 Garden market. It is used, boiled in milk, 

 for diseases of the lungs. They are also sent 

 to America from this country as a delicacy. 



These animals become torpid about October 

 (at least in England), and remain so during 

 the winter, having first closed the mouth of 

 their shells with an epiphragma which they 

 throw off, and emerge when warm weather 

 returns. Some of them form two or three of 

 these doors, one within the other, so as com- 

 pletely to exclude the cold; and others bury 

 themselves in the earth. The Helix aspersa, 

 M 4 



