142 TESTACELLID^E. 



monograph by MM. Gassies and Fischer, published at 

 Paris in 1856. 



The Testacella appears to be the only land-mollusk 

 which has truly predaceous habits ; its marine representa- 

 tives in this respect being the Cuttle and the Whelk. It 

 is scarcely inferior 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 longer 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 its 

 mouth is furnished with an apparatus of sharp recurved 

 teeth, which enables 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 occasionally 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 to wards 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 rings. 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 which means the rings are 

 forced open, its purpose is effected and the meal secured. 



