284 THE ZOOLOGIST. 



to the tiger, snake, or shark in its cunning and ferocity. Its prey 

 chiefly consists of earth-worms which it hunts underground, and 

 pursues through their galleries, crouching occasionally and 

 making a spring on its victim. It is said that when the poor 

 worm has had the start of its pursuer the snail-slug intercepts it 

 by tunnelling across the line of its retreat. It will devour a 

 lob-worm much larger than itself, seizing it in the middle, and 

 when the writhings have been succeeded by exhaustion, it 

 detaches and swallows one-half of the worm, and after that has 

 been digested it finishes its long meal with the other portion. 

 For this purpose the mouth is furnished with sharp recurved 

 teeth, which enable the Testacella to retain a firm hold of its 

 victim and swallow it more easily. The worm is provided with 

 some means of defence in the rows of stiff bristles which encircle 

 its rings, and by contracting its body a short respite is gained. 

 But the chance of ultimate escape or safety is very slight. 

 When the Testacella sees or scents its prey, it glides softly and 

 cautiously towards it, and apparently without taking any notice 

 of the worm, it seems to feel its way, and usually succeeds in 

 fastening itself on an unprotected part of the body between the 

 ring. The attack if unsuccessful at first is renewed, but if the 

 worm resists too long the Testacella gets impatient, and by 

 pressing or doubling its victim into the earth, by means of which 

 the rings are forced open, its purpose is effected and the meal 

 secured." The idea that the slug detaches half the worm does 

 not seem to be supported by facts. Ferussac* certainly does 

 say, apparently following Faure-Biguet, that half the worm is 

 inside, half out, but does not intend to give the impression that 

 the halves are separate. The meaning of the last statement in 

 Jeffreys' account, if taken by itself, would be a difficult matter to 

 determine, for if the attack, as stated, were unsuccessful, by what 

 means could the Testacella hold a startled worm while pressing 

 it into the earth ? But, if we refer again to Gassies and Fischer, 

 where they describe the Testacella, the following passage will be 

 found : — " Si elles ne reussissent pas du premier coup, elles font 

 glisser peu a peu le corps de l'animal jusqu'a ce qu'elles soient 

 arrivees a leur but, mais si le ver resiste trop, elles plongent la 



* 'Histoire Naturelle des Mollusques' (1811—32), vol. ii. p. 92. 



