CHAPTER II. 



A Ramble over the London Clay Shells in London Gardens Medi- 

 cinal properties of Snails Other Garden Snails Snails in Hyde 

 Park Riverside Species The Shell Slug. 



IN the last chapter we promised to say something of 

 the land and fluviatile mollusca inhabiting the London 

 clay. Those who possess gardens in the metropolis 

 and its environs may not be prepared, perhaps, to 

 learn that they may commence a collection of shells 

 before leaving their own premises ; yet such is the 

 case. There are certain species so generally dis- 

 persed, or of such an accommodating nature, as to 

 find an existence in that generally barren territory 

 where the only birds are sparrows, and the indigenous 

 animals cats. Others, no doubt, get introduced 

 with plants and shrubs, and ultimately become, s.o 

 to say, acclimatized. 



The commonest species naturally presents itself first 

 to our notice ; but in referring to this, the ordinary 

 garden snail, Helix aspersa (PL L, fig. 3), which 

 must be sufficiently familiar to all, it will only be 

 necessary to do so in order to point out a few facts 



c 2 



