56 MOLLUSC A, 



snails, interesting from the great variations of the shell. 

 The eggs are laid in capsules (Fig. 69), in a jelly-like 

 mass, late in the spring. In the winter they hibernate in 

 the mud ; 320 species are known. 



Land-Snails (Helicidcz}. Three thousand three hun- 

 dred and thirty-two species of these are known in various 



FIG. 70. Air-breathing gasteropods : Snails and slugs. A, garden snail 

 (Helix) ; B, B, slug Testacella one disappearing into the ground, and 

 only the tail showing ; C, the great gray slug (Ltmax} ; s, shell ; /, ten- 

 tacles ; e, eyes ; , breathing-hole. 



parts of the world. *They are easily kept in a fernery and 

 their habits watched. Many of the snails (Fig. 70, A) de- 

 posit large white or yellow eggs with a calcareous covering. 

 The Bulimus (Fig. 71), an ally, rolls two leaves together 

 and fastens the eggs between. Some of their eggs are as 

 large as a pigeon's, 



