SHELLS. 225 



living undef ground, and feeding principally on 

 earth-worms ; viz. the Testacella haliotidea. 



3. Vitrina : species Vitrina pellucida — shell minute, 

 earshaped, slightly spiral at its summit; aperture 

 large. When the aperture of the shell assumes a 

 crescent-like figure, and the lunated aperature is 

 wider than it is deep, the shells belong to Helix. 

 In some, the shell is globular. 



4. Heliss. — Shell globular, spiral, varying very 

 much in its form, and receiving the body more or 

 less completely. The species observed here are not 

 very numerous. Heliss concava and H. hortensis are 

 commonly observed. The great majority of the 

 species deposit a number of eggs glued together into 

 a mass, and concealed under rubbish, the bark of 

 decaying trees, dead leaves, or moss, or beneath the 

 surface of the ground. 



5. Pupa. — 'The species are very small, living in 

 moist situations, amongst mosses, &c. One species 

 is very common here, the Pupa chrysalis ; they 

 derive their name from the resemblance of the shell 

 in shape to the pupa or chrysalis of an insect. 

 The animal resembles the Helix. 



6. CTaMsi&.-^Clausilia papillaris is a type of 

 the genus, resembling the Helix in shape, but more 

 slender. 



