290 NATURAL HISTORY OP OUR SHORES 



It was by the merest chance that I saw it, although it was 

 out of water, and fully exposed. It fell a victim to the 

 camera, and is shown in Fig. 77. 



Now this mimetic artifice is very common in the Maidce. 

 I have mentioned instances in the chapter on the " Crus- 

 tacea," and given some figures. 



Perhaps, to some extent, some of the smaller Crustacea 

 may be proper mimics ; for instance, the skeleton shrimps 

 (Caprella) live among the branches of zoophytes and polyzoa, 

 and their linear, and sometimes tuberculated (C. acanthi/era), 

 forms correspond with the branches ; their colour is also the 

 same, but the form may only be due to adaptation to 

 habit, being just the correct one for climbing between close - 

 set branches. 



The long legs of Stenorhynchus (Fig. 79) seem built for 

 speed, but these crabs are the most sluggish of all the crab 

 tribe, so their use may be, when bits of weed are attached 

 to them, to imitate the delicate branched sea-weeds. 



And yet, structurally the same, Inachus (Fig. 82) does 

 not deck itself ; it has no hooked hairs, and usually lives 

 fairly in the open, clinging to the vertical side of a rock, 

 whence it generally topples down when the tide recedes, 

 and lies there upon its back. Its legs only seem to render 

 it the more conspicuous. 



True, its shell is of such texture, terracotta-like, that 

 the embryos of sponges and the larvae of ascidians readily 

 attach themselves to it, thus helping to disguise it, but 

 still it is conspicuous. And yet it must be good to eat ; 

 defenceless, inactive, conspicuous, and its reproduction not 

 very great for a crustacean, the eggs being large and com- 

 paratively few. This is another puzzle. 



When we arrive at the fishes, we find, as in the cephalo- 

 pods, striking evidence of the value of colour and marking. 

 In the fishes that habitually swim at some distance from 

 bottom the dark tint of the back and the white or silvery 



