MOLLUSCA. 65 



made very fat ; on the approach of winter they retreat 

 entirely within their shell, the mouth of which they close 

 up with a kind of calcareous substance. Thus enclosed, 

 and safely embedded in the earth or in hollow trees, they 

 remain torpid until spring. Whilst thus voluntarily im- 

 prisoned, they are used as food, and being boiled in salt 

 water, are considered as being both savory and whole- 

 some. They deposit their eggs, which are about as large 

 as peas, during the summer season, in cavities of the 

 earth. A great variety of snails, larger or smaller, 

 some with flat, others with spiral, or oblong shells, are 

 found in gardens. They are so numerous as to be con- 

 sidered as pests, and do great injury to vegetables, with- 

 out being useful in any possible way. 



The Midas Ear (bulla haemastornus) is three or four 

 inches long and two inches in thickness. It is found in 

 the forests of Brazil. In many places these snails are 

 valued on account of their shells, Avhich are of a pale-red 

 color and very thick, and are used by the lime burners. 

 The eggs are as large as those of a pigeon. Another of 

 the species, very large, and the handsomest specimen of 

 the terrestrial snail, is 



The Zebra Snail (bulla zebra), the shell of which is 

 five inches long, white, with brown spiral stripes, and 

 found only at the Cape of Good Hope. 



The Common Water Snail (helix stagnalis) abounds 

 in all our pools, and may be seen swimming on the sur- 

 face of the water. The length is about one inch and a 

 half. They are sometimes kept in glass jars, and fed on 

 duck weed, etc. They lay their eggs on water plants, 

 and the shell or covering is so very transparent, that the 

 movements of the young snail enclosed within, are 

 clearly discernible. 



