224 



TYE : NOTES ON THE EPIDERMIS OF MOLLUSCA. 



I subjoin a list of such species of Helix as I know have a 

 hispid epidermis, with their place of habitat : — 



There is a field of interesting research for conch ologists in 

 trying to work out the cause and uses of this peculiar structure; 

 why molluscs having a hispid coat should be sombre coloured, 

 shy and retiring in habit, unlike their more brilliantly coloured 

 brethren. As the smooth epidermis serves as a protective coat 

 for the shell, there would seem to be a further use for a hairy one 

 other than merely as a conserving agent against erosion. 



Helix sericea has a habit of creeping over leaves in damp 

 weather and of dropping immediately it perceives the proximity 

 of danger, the slightest touch is sufficient to cause it to loose its 

 hold, and so silent is the fall, broken by its springy coating of 

 hairs, that even though it be from a considerable height, it is not 

 heard, and it receives no hurt however far it falls. This habit 

 is shared by H. hispida in a less degree. 



The hairs may be irritating to creatures apt to prey upon 

 snails — birds or frogs ? It is most perfect and in finest condition 

 during those periods in which the creatures possessing it are 

 most active, for the hairs being hygrostatic then become erect. 



J.C, v., July, 1S87. 



