THE FOOT-JAWS AND THE JAWS. 23 



is longer than the rest, and strongly toothed along the 

 inner edge, or that which is turned towards its fellow. 

 It is obvious that these two limbs are well adapted to 

 crush and tear whatever conies between them, and they 

 are, in fact, jaws or organs of manducation. At the same 

 time, it will be noticed that they retain a curiously close 

 general resemblance to the hinder thoracic legs ; and 

 hence, for distinction's sake, they are called outer foot- 

 jaws, or external maxillipedes. 



If the head of a stout pin is pushed between these 

 external maxillipedes, it will be found that it passes 

 without any difficulty into the interior of the body, 

 through the mouth. In fact, the mouth is relatively 

 rather a large aperture ; but it cannot be seen without 

 forcing aside, not only these external foot-jaws, but a 

 number of other limbs, which subserve the same function 

 of manducation, or chewing and crushing the food. We 

 may pass by the organs of manducation, for the present, 

 with the remark that there are altogether three pairs of 

 maxillipedes, followed by two pairs of somewhat differently 

 formed maxilla, and one pair of very stout and strong 

 jaws, which are termed the mandibles (4). All these jaws 

 work from side to side, in contradistinction to the jaws 

 of vertebrated animals, which move up and down. In 

 front of, and above the mouth, with the jaws which 

 cover it, are seen the long feelers, which are called the 

 antenna (3) ; above, and in front of them, follow the 

 small feelers, or antennules (2) ; and over them, again, lie 



