114 UNIVALVES. HELIX. 



H. ampullacea, tl. glauca, and H. pomatia; the latter snail 

 is an inhabitant of the woods of Europe, and was intro- 

 duced into England by Sir Kenelm Digby, for medical 

 purposes. The animal is used in many parts of Europe 

 as an article of food during Lent, and was considered a 

 luxury by the Romans. It is oviparous, and very tena- 

 cious of life; towards winter, it covers its aperture with 

 a calcareous lid, resembling an operculum, and remains 

 in a torpid state until the spring. The animal of the 

 H. ampullacea grows to an immense size, and is also eat- 

 en; its eggs, which it deposits in clusters on the bark of 

 trees, or rushes, &c. have sometimes a pink tinge, but are 

 generally dull white. The H. ovalis and H. oblonga are 

 both land shells; the eggs of the animal are perfectly el- 

 liptical, and nearly equal in size to those of the common 

 sparrow. 



The rounded and imperforated species compose the 

 third division : of these may be adduced the H. dextra 

 and the H. perversa, which differ only in the direction 

 of their whirls: they are both rare shells, and have their 

 surfaces covered with a beautiful citron color, variegated 

 with green, and striped or banded with brown. The ani- 

 mal of the H. ianthina has the property of emitting a 

 phosphorescent light, and stains the hand of a purple co- 

 lor, not easily removed j they are found in great numbers, 

 floating on marine substances. 



Amidst the endless variety of terrestrial shells there is, 

 perhaps, no species so well known as the H. hortensis or 

 common garden snail; it is an inhabitant of European 

 gardens and orchards, and very destructive to fruit and 

 tender leaves. Its eggs are perfectly round, and about 

 the size of small peas. 



A very beautiful and rare species of this division is 



