THE MAILED WARRIORS OF THE SEA. 163 
been modified to suit their lives. Thus for example, 
while the prawn uses his second pair of feet for 
catching and holding his prey, it is the front feet of 
the crab and lobster which carry the large strong 
claws, and in the shrimp these front feet have a kind 
of broad hand at the end, with a hook attached. 
Again, the skeleton of the prawn remains clear and 
transparent, but the warlike crab and lobster secrete 
layers of lime in their skeleton, forming a stony coat 
Fig- 57- 
T, Sandhopper.* e, Flat eye. C, Skeleton Shrimp, f g, Breathing gills. 
Then again if you look at the nimble sandhopper 
(T, Fig. 57), with eyes flat in its head instead of being 
raised on stalks, you will notice that all its body is 
ringed right up to its head, so that it can bend itself 
almost into a circle, and flinging back its tail with a 
jerk, spring about in the sand. 
In the skeleton shrimp (C, Fig. 5 7), which crawls 
about among the weeds under water, the body has 
* Talitrus. + Caprella. 
