26 CRUSTACEA. 



budding out, or two bodies uniting " in coitu,' 1 is the re- 

 production of the original image with more or less fidelity, 

 according to the law that like tends always to reproduce 

 like. Any dealer in lobsters can obtain these deformed 

 arms, if he chooses to take the trouble. 



In front of the large arms arc the three pairs of jaw- 

 feet or maxillipeds (big. .^. />', J i-d 3). These are 

 well named, for thev are transitional forms between the 

 true legs and the mandibles. The third pair (d $) pick 

 up and hold whatever food lies quietly upon the bot 

 torn, at the same time that the large arms are ex- 

 tended forwards, ready to seize and kill the active 

 prey which comes within their reach. The inner por- 

 tion of this pair of maxillipeds is cA^cd by two serrated 

 blades which hold the food and assist the jaws in tear- 

 ing off pieces of the right size. It is then apparently 

 bitten and (hewed by the other jaw-feet, by the two 

 pairs of little jaws or maxilke (Fig. 8, />', c 2 ; A, C I. 

 Fig. 9. <" 1 ). which are perpetually moving, and lastly 

 by the hard, strong grinders or mandibles ( Figs. X, q, 

 9 A, I'). The structure of the maxilke, however, 

 shows that they" are not of any real use in the matter 

 of chewing. Their inner edges are hairy, and not 

 spinous or toothed, or thickened in any way. as would 

 be the case if they were accustomed to such hard 

 usage. 



The mandibles, on the other hand, are powerful, 

 trenchant blades, and are placed one on each side of the 

 mouth (Figs. 9, 9 .-/. ;//),so that they open laterally in- 

 stead of vertically. This is necessarily the characteristic 

 of all the opposable organs of the lower animals which 

 are formed out of pairs of appendages. Appendages are 



