SLUGS. 89 



it again here to note that it is not uncommon 

 beneath the bark of old hawthorns on the downs, 

 and may be found also on old willows and ash 

 trees, and on walls beneath ivy. 



The true slugs, which remain to be noticed, do not 

 possess the same interest for collectors as the snails ; 

 for, although they are not, strictly speaking, shell- 

 less, their shells are comparatively insignificant, 

 while the repulsive appearance of the animals fre- 

 quently causes them to be purposely avoided. 



The popular belief that slugs are only snails, 

 which for some reason best known to themselves 

 have temporarily vacated their shells, is not confirmed 

 by the observations of malacologists, who, on the 

 contrary, have long been aware of the fact that slugs 

 are really possessed of shells of their own — of which, 

 to say the least, they would find it extremely difficult 

 to divest themselves. 



We have already alluded to the prominence on the 

 back of the slug ; this is the mantle, on the under 

 surface of which the shelly secretion is spread out in 

 the form of a thin plate, and the latter from its posi- 

 tion, is no doubt designed as a protection to the 

 important organ beneath it. This plate, as may be 



