COLORATION AND MIMICRY 289 



conger. A large conger disposes of a very fair-sized octopus 

 at a mouthful bolus. 



The term mimicry in its restricted and actual sense is 

 when some animal, good to eat and defenceless, imitates in 

 size, form, and colour some other that it is not safe to 

 attack, as in the case of the great saw-fly (Sirex gigas), 

 which is juicy and harmless, but saves itself by mimicking 

 a hornet, and hundreds more ; or imitates some inanimate 

 object which would not be noticed, like the " stick " and 

 " leaf " insects, which are exact imitations of twigs and 

 leaves ; also the Kallima butterfly, etc. 



In its broader application the term is used when some 

 animal, like the cephalopods,just mentioned, simply imitates 

 surroundings. 



Of the latter system of mimicry there is abundance 

 among our shore animals, but of the former the instances 

 are rare, for it may be straining a point to say that the 

 little, nobbly, pink coloured " Nut Crabs " (Ebalia) mimic 

 the nullipores and small pebbles of their home. (I have 

 just said " on our shores" for in foreign examples genuine 

 mimicry is very apparent.) 



I have a large crab (Parthenope horrida) from some tropical 

 place (I have no data), and with it a bit of the bottom 

 that was dredged with it. Although the crab is six inches 

 in diameter it is not easy to tell where it begins or ends 

 on the cake of hardened, calcareous bottom. This crab is 

 of the shape of our own little Eurynome aspera, and its 

 angles, rugosities, and colour are identical with the 

 ground. 



This very day I was face to face with a large male Pisa 

 tetraodon. It was sitting up, in a nearly upright position^ 

 near a raised bank, on which Zostera was growing. It had 

 decked itself with a couple of bits of Zostera, firmly fixed 

 to the hooked bristles between its bifurcate rostrum, and 

 these stood upright, just as if growing from a clump of mud. 

 T 



