56 EVENINGS AT THE MICEOSCOPE. 



marks of progress which each operator leaves behind 

 him. Though the confervoid plants are swept oif by 

 the tongue of tlie Mollusk, it is not done so cleanly but 

 that a mark is left where they grew ; and the peculiar 

 form and structure of the tongue, which I have above 

 noticed, leave a series of successive curves all along the 

 course which the Mollusk has followed, very like those 

 which mark the individual swathes cut by the mower 

 in his course through the field. 



The Periwinkle's table-manners differ slightly from 

 those of his relations. When he eats, he separates two 

 little fleshy lips, and the glistening glass-like tongue is 

 seen, or rather the rounded extremity of a bend of it, 

 rapidly running round like an endless band in some 

 piece of machinery ; only that the tooth-pointSj as they 

 run by, remind one rather of a watch-wheel. Eor an 

 instant this appears, then the lips close again, and pres- 

 ently reopen, and the tongue again performs its rasp- 

 ing. It is wonderful to see ; — ^perhaps not more won- 

 derful than any other of God's great works, never more 

 great than when minutely great ; but the action and 

 the instrument, the perfect way in which it works, and 

 the effectiveness with which the vegetation is cleared 

 away before it, all strike the mind with more than usual 

 force, as exhibitions of creative skUl. 



As the Periwinkle moves along, mowing his sea- 

 grass as he goes, he carries before him two soft and 

 flexible horns, marked with zebra-like bands of black 

 and white, which he constantly waves about. These 

 are organs of some sense, probably of touch, and are 

 therefore called tentacles (or tryers) ; but they bear on 

 their outer sides, near the base, a pair of other organs, 

 which are more closely analogous to what we ourselves 



