i 5 4 CRUSTACEANS. 



side of the mouth, which are evidently adapted to assist in seiz- 

 ing and conveying into the mouth the substances used as food. 



These singular organs, although entitled to "be considered as 

 jaws, so far as their use would indicate, are no less obviously 

 merely modifications of jointed legs ; they are, therefore, termed 

 "foot-jaws," or "jaw-feet." 



. 158. COMMON LOBSTER. 



The pair of legs that come next are developed to a size far 

 surpassing that of the other limbs, and are endowed with pro- 

 portionate strength. Each of these robust extremities is termi- 

 nated by a pair of strong pincers (cliche] ; but the two differ in 

 their structure, and are appropriated to different uses. That of 

 one side of the body has the opposed edges of its terminal forceps 

 provided with large blunt tubercles, white the opposite claw is 

 armed with sharp teeth. One claw, in fact, is used as an anchor, by 

 which the lobster holds fast by some submarine fixed object, and 

 thus prevents itself from being tossed about in an agitated sea ; 

 the other is a cutting instrument for tearing and dividing prey. 



To the chelce succeed four pairs of slender legs, scarcely at all 

 serviceable for locomotion, but the two anterior, being terminated 

 by feeble forceps, arc auxiliary instruments of prehension. 



