22 TYE I A CASE OF PROTECTIVE RESEMBLANCE AMONG SLUGS. 



Where the semblance is most perfect we get the keel, pallia] 

 line, sometimes the corrugated surface, occasionally the partly 

 extended tentacles, the darker lines often seen on A. hortensis, some- 

 times the curve of the body sideways, as in the act of turning, and 

 in one case I noticed a sheath had fallen on the edge of a brick, and 

 it was scarcely possible to believe it to be other than a slug with its 

 head bent over in the act of passing the angle. 



The natural exudation of resinous gum — which has a somewhat 

 pleasant odour — gives a rather shiny appearance to the sheaths even 

 in dry weather, and when they are wet this slug-like appearance is 

 enhanced. 



It sometimes happens that the bloom falls off with two parts of 

 the sheath attached, then the husk looks exactly like a slug feeding 

 on the peduncle of the flower. 



It is perhaps worthy of remark that activity among the slugs is 

 coincident with the fall of these bloom-sheaths, at a time when con- 

 cealment is useful to them on account of the increased energy of 

 their natural enemies, the thrushes, who, after a winter's ahstinence 

 from such dainties, are more than usually alert, having young to 

 provide for. 



It is true slugs are where poplar trees are not — but the case 

 I cite is probably one out of many, which further observations 

 will elicit. 



If we consider the general colours of slugs, sombre greys and 

 browns, we can readily see how curled leaves, sticks, sheaths, &c, 

 help them against their foes — a flash of deception has many a time 

 passed through my mind by seeing some such object which looked 

 like a slug. 



" I know a bank," a sweet bank by Warwick's " soft flowing Avon," 

 where, in the gloaming, a pale A. agrcs/is — a species which is very 

 plentiful there— creeping up a grass stem looks like a cocoon of the 

 five spotted Burnet-moth {Zygcvna trifolii). At such times when the 

 sun is not shining, the mind, through the eye, is easiest deceived in 

 man, and probably in beast too. The little A. bonrguignati, when 

 you find it under a log or stone " humping itself," looks like a 

 grey pebble, and the great Limax maximus seems at first glance 

 something more villainous than a slug to other eyes than ours, 

 perhaps. 



These are bald notes on a subject of great charm to a naturalist, 

 showing how life has struggled and worked to one great end- — to fit 

 itself to its environment. 



