hand-slugs and Glass-shells 339 



their shell to keep out the cold. As shown in our 

 figure the shell is slightly invested by the mantle, 

 which has a lobe on the right side, and this is 

 turned up over the shell when the animal is active. 

 Such a habit of shell-investment extended, as we 

 have seen it in many marine species, until the 

 shell is completely hidden, may have brought 

 about the conditions existing in Limax where the 

 shell is reduced to an almost flat plate and is 

 quite hidden away. The Glass-snail has a quaint 

 habit, which is no doubt protective, of giving a 

 vigorous jerk to its tail when alarmed, and so it 

 throws itself ofl* from the twig or stone it may be 

 gliding on and drops among the moss below. It is 

 everywhere plentiful in suitable situations. It ap- 

 pears to be as much carnivorous as herbivorous, 

 sometimes attacking in force a sickly earthworm, and 

 showing a liking for horse-droppings. These traits 

 are shared by the next genus, Hyalmia, in which 

 the shell is sufliiciently roomy always to accommodate 

 the entire animal. 



Draparnaud's Snail {H. drcqxirnaiidi) is the largest 

 of the genus, of which there are ten native species. This 

 one is exceedingly local, and has been found only in 

 Guernsey, Falmouth, Torquay, Bristol, and Isleworth. 

 The shell is al)Out three-quarters of an inch across, 

 glossy, reddish above, wdiitish beneath. Mouth an 

 oblique oval; umbilicus large. A common species 

 that may be confused with the foregoing is the so- 

 called Cellar Snail {H. cellari<i), which scarcely 

 exceeds half an inch across, but it is flatter above, 

 more yellow than red, whilst below it is distinctly 

 white, though sometimes with a greenish tinge. As 



