92 



ETON NATURE-STUDY 



tion of the silvery trail they are accustomed to leave behind them. 

 Another striking point with regard to slugs, is the way in which 

 some of them can let themselves down from trees or other places 

 by means of a thread 

 of slime, which often 

 may extend to several 

 feet in length, and 



which is so tenacious 

 that some times a 

 slug can climb up it 



again . 



i 



FIGURE 207. A worm-eating Slug. 



Besides these shell- 

 less and more familiar 

 slugs, there are one or 

 two in this country which live underground and feed on worms 

 which they seize and swallow. The remarkable organ by means of 

 which the snail rasps off its vegetable food, is in their case so enlarged 

 that it can be protruded to some distance from the 



mouth, and the sharp spikes with which it is seen 

 to be beset are (as can be easily proved under the 

 i microscope) strongly barbed at the point like a 

 1 fish-hook.* An interesting series of observations 

 may be made upon the worm-eating slugs, for by 

 gently touching them with a paint brush they 

 may be led to imagine that they are meeting a 

 FIGURE 208. The egg worm in its burrow, and induced to thrust out 



of a worm-eating Slug. ^^ t(mgue> Jf ft worm be glowed to Crawl 



against the front of one of these slugs, it will very often endeavour 



* See " The Manner of Feeding in Testacella scutulum." By Wilfred Mark Webb, 

 F.L.S. The Zoologist, Series 3, Vol. XVII (August 1893), pages 281-289, Plate 1. 



