SNAILS AND SLUGS 55 



districts. This slug and its relative, Arion minimus, are the only 

 species capable of contracting the body into a hemispherical 

 lump when alarmed. A. minimus may be distinguished from 

 juvenile examples of A. ater by the presence of bands of colour 

 on the sides of the body, and by the regular symmetrical rows 

 in which the pointed warts covering the surface are arranged. 



The cellar slugs, Limax maximus and L. ftavus, are familiar 

 examples of the family Limacidce. As their popular name indi- 

 cates, they are frequently to be found in cellars, but they also 

 occur in holes in walls and beneath logs in damp situations. 

 As in Arion ater, the colour of these species too is very variable, 

 but the bluish colour of the tentacles of L. ftavus will serve to 

 distinguish that species from L. maximus. Another member 

 of the same genus is the " Tree Slug/' L. marginatus, which is 

 more abundant in the north than in the south of England. 

 Reference has already been made to the habits of this snail. 



The " Snail Slugs/' or Testacellidce, form a third family 

 intermediate between the snails and slugs proper. As already 



FIG. 34. Testacella. 



mentioned, these animals bear a small though quite distinct shell, 

 and are carnivorous in their diet. In habits they are nocturnal 

 and subterranean, burying themselves deeply in the soil. They 

 may, however, be found upon the surface and upon walls after 

 heavy rains, when the earth has become saturated with moisture, 

 and in consequence the process of breathing difficult. 



Neither snails nor slugs are difficult to keep in captivity. 

 Almost any vessel with a lid will serve as a cage, and they will 



