102 NUTRITION. 



(Echinus,) this apparatus, which has been called Aristotle's 



Fig. 55. Fig. 56. 



lantern, (Fig. 56,) consists of numerous pieces, and is much 

 more complicated. Still, the five fundamental pieces or jaws, 

 each of them bearing a tooth at its point, may be recognized, 

 as in Scutella; only instead of being placed horizontally, 

 they form an inverted pyramid. 



213. Among the Mollusks, a few, like the cuttle-fishes, 

 have solid jaws or beaks closely resembling 



the beak of a parrot, (Fig. 



57,) which move up and 



down as in birds. But a 



much larger number rasp 



their food bv means of a flat 



tf 



Fig. 57. blade coiled up like a watch- Fig. 58. 



spring, the surface of which is covered with innumerable 

 minute tooth-like points of a horny consistence, as seen in a 

 highly magnified portion of the so-called tongue of Natica, 

 (Fig. 58, a,) which, however, is only a modification of the 

 beaks of cuttle-fishes. 



214. The Articulata are remarkable, as 

 a class, for the diversity and complication 

 of their apparatus for taking and dividing 

 their food. In some marine worms, Nereis, 

 for example, the jaws consist of a pair of 

 Fig. 59. curved, horny instruments, lodged in a 



sheath, (Fig. 59.) In spiders, these jaws are external, and 





