SHRIMPS. 163 



succeeding pairs of legs, unlike those of the lobsters, are of great 

 size and strength, and instead of being terminated by pincers, 

 end in strong pointed levers, whereby the animal can not only 

 crawl, but drag after it its heavy habitation. Behind these loco- 

 motive legs are two feeble pairs, barely strong enough to enable 

 the soldier crab to shift its position in the shell it has chosen, and 

 the false feet attached to the abdomen are still more rudimentary. 

 But the most singularly altered portion is the fin at the end of 

 the tail, which here becomes transformed into a kind of holding 

 apparatus, by which the creature retains a firm grasp upon the 

 interior of its residence. 



FOOT-MOUTHED CRUSTACEANS. ORDER STOMAPODA.* 



The Stomapoda (Foot-mouthed Crustaceans) are so called 

 because their feet are collected in the immediate vicinity of the 

 mouth. In this order the principal organ of locomotion is the 

 tail, which, broadly spread and armed with a beautiful expansion 

 at its extremity, carries beneath it the false feet, here developed 

 into five pairs of broad leaf-like organs, which constitute the in- 

 struments of respiration. The integuments of the Stomapods 

 are thin and almost membranous. 



FIG. 165. MANTIS SHRIMP. 



The Mantis Shrimp (Squilla mantis] is remarkable on account of the strange 

 resemblance between its fore-legs and those of the insect Mantis, described in a pre- 



* oTo/xa, stoma, the mouth ; TTOVS, pous, afoot. 



112 



