TESTACELLA. 237 



externally on the hinder part of the back, with the opening 

 of the pulmonary cavity under its edge. Should any one 

 fond of gardening be fortunate enough to find, within the 

 enclosure, this slug with a shell on its tail, let him not destroy 

 it, but let it live, and it will multiply : it is an enemy to his 

 enemies; it is carnivorous, and its favourite food is the 

 vegetable-devouring slug. Burrowing deep in the ground 

 in winter, it only comes to the surface to devour such nox- 

 ious creatures as may come in its way. The Testacellce 

 however do not multiply very fast, and the contents of the 

 stomach sometimes show that they have not scrupled to 

 devour smaller specimens of their own species. 



