The Rev. P. Keith on the Structure of Animals. 93 



the body externally divided into a succession of rings, or arti- 

 culations. They are distributed into the three following 

 classes : The Vermes, or worms, in which the body is without 

 any external organs of locomotion ; the Crustacea, in which 

 the body is covered with a shell ; and the Insecta, or insects, 

 in which the body is divided by deep indentations into four 

 principal parts,— the head, the corselet, the chest, the ab-* 

 domen. 



Class 1. The first class is exemplified in Lumhricus teV" 

 restris, — the earth-worm. At its mature size it may be about 

 a span in length, with the circumference of a goose-quill. The 

 head is indistinct, but the mouth is not so. The body is soft 

 and gelatinous, and articulated on the external surface, with a 

 sense of touch chiefly about the two extremities ; but without 

 any external and distinct organ, whether of hearing or of 

 sight, and without feet, but covered with projecting bristles, 

 or tufts of hair, which in some measure supply their place. 



Class 2. The second class is exemplified in the crab and 

 lobster, shell-fish that are well known. They inhabit rocky 

 shores, or shallows of the ocean, and feed upon sea-weed and 

 all manner of garbage. The head is furnished with feelers and 

 with moveable eyes. The legs are eight or ten in number, 

 with five articulations, the first pair ending in claws or nip- 

 pers, and, like the body, covered with shell. If they lose a 

 limb by accident, they have the power of reproducing it. 

 Lobsters have a long and articulate tail, covered with a horny 

 coat, composed of several portions that move one upon another. 

 They shed their shells annually, and screen themselves for a 

 few days under the shelter of stones and rocks till the new 

 shell is sufficiently indurated to defend them from the ordinary 

 accidents to which the element they inhabit exposes them. At 

 last they are caught by the art of the fisherman, and forwarded 

 to the tables of the lovers of luxuries, where they are much 

 esteemed for the delicate morsel, or for the rich and piquant 

 sauce which their edible portion affords. The natural colour 

 of the lobster is black ; but when boiled it changes to red, — a 

 circumstance that the author of Hudibras has turned to good 

 account in the getting up of one of his ludicrous similes : 



•* The sun had long since, in the lap 

 Of Thetis, taken out his nap ; 

 And, like a lobster boiled, the morn 

 From black to red began to turn." 



Hudibras, part ii. cant. 2. 



Class 3. The third class is exemplified in the silk-worm, 

 PhalccnaMori. If in its native country of China or of India, 

 it lays its eggs in summer on the boughs of the mulberry-tree. 



