78 STRUCTURE OF MOUTH. 



Dr. Johnston inclines to this opinion, and assigns as his reason 

 the fact, that when the little fellows have been snugly stowed 

 away inside their shells, he has sometimes tempted them out by 

 bringing near to them a little fresh food. But one thing is very 

 certain they have the sense of taste, and are doubtless good 

 judges of flavour. M. Gaspard (a great authority on Snails) 

 disallows the tribe all the senses save those of taste and touch, 

 the latter of which he admits they possess in an extreme degree 

 of delicacy. The sense of taste ought to be well developed ; for, as 

 the whole family are extraordinary eaters, one large source of 

 pleasure would be lost to them if they did not enjoy their food. 

 Mr. Gosse has a very graphic description of the Periwinkle in 

 the act of mowing down his dinner of minute conferva from the 

 glass sides of an Aquarium : the Snail is an equally interesting 

 subject at dinner-time, though his method of feeding is a some- 

 what different one. On the upper side of the opening of his 

 mouth there is a semicircular horny jaw, which, by pressing 

 against a sort of pad on the floor of the mouth, cuts off the frag- 

 ments of its leafy food. But, besides the jaw and its pad, there 

 is a pair of very serviceable lips, and a little membranous tongue, 

 roughened over with minute prickles, all set in regular array, 

 and pointing backwards, so as to retain more securely the food 

 it has to manipulate. A Snail's tongue, by the way, is an 

 object of no little interest ; and if any one doubts the statement, 

 let him ask the opinion of any microscopical observer, and he 

 will say you could hardly have a more interesting object to look 

 at. The little points or prickles above mentioned are arranged 

 so orderly and methodically, and in such pretty patterns more- 

 over, the different sorts of Snails exhibit such a great variety in 

 the shape of the tongue itself that they deserve to be ranked 

 amongst the fairest specimens of Nature's dainty handiwork. 



But we were going to exhibit a Snail in the act of dining. 

 When the little fellow is about to eat, then, it pushes forward its 

 prickly tongue, at. the same tune protruding the lips on each side, 

 till they both come in contact with what is designed to form the 

 first mouthful. The lips then seize hold of the food, and draw 

 it towards the aperture of the mouth, the tongue at the same 

 time keeping it secure by the array of reverted prickles. Brought 

 in this way within range of the horny jaw, the food is pressed 

 upwards, and a small portion a Snail's mouthful detached; 



