33G Colonel C. Swinhoe on 



prey. But this is not an aggressive resemblance only, but a 

 protective one, because it is very good food, greedily devoured, 

 and it obtains protection from its extraordinary likeness to its 

 surroundings. 



The next example is from life of the pipe-fish [Siphonostomn 

 ti/phlc). This creature obtains its protection by being coloured 

 like the grass amongst which it lives, Zostera, a grass-like 

 flowering plant which is found in the sea, like sea-weed. The 

 pipe-fish stands up in it like a piece of grass, and sways backwards 

 and forwards with the current in the same way as the grass. 

 This example is taken from life from the Plymouth Aquarium. 

 An interesting example of adventitious protection is afforded by 

 certain crabs [Stenorhynchus, an English spider-crab), which 

 fasten pieces of sea-weed on their bodies and limbs. Some of 

 these may be observed in the cases your President has been good 

 enough to bring ; the exhibits were taken from life in tlie 

 Plymouth Aquarium, and I think very fairly represent the 

 creatures themselves. Mr. Poulton tells us in his book on the 

 colours of animals that Mr. Bateson has observed the process. 

 The crab takes a piece of sea-weed in his two chelae, and without 

 either snatching or biting it, deliberately tears it in half as a 

 man tears paper with his hands. He then puts one end of it in 

 his mouth, and chews it up, presumably to soften it. He then 

 takes it out, and rubs it firmly on his head or legs until it is 

 caught by the peculiar curled hairs which cover them. If the 

 piece of weed is not caught by the hairs, the crab puts it back in 

 his mouth and chews it up again. The whole process is very 

 human and purposeful. This crab is a very favourite food for 

 some fish, and, as your President has just reminded me, the fish 

 never eat sponges, these creatures cover themselves with sea- 

 weed and sponges, so that they can thus be hidden by something 

 which their own enemies object to. 



Next we come to true mimicry, where one creature is protected 

 by its resemblance to another. The general observation of all 

 the writers on this subject is that imitating species are com- 

 paratively rare, often very rare, whilst the imitated are to be 

 found in great numbers, the two living together ; the imitated 

 are protected species, being distasteful, whereas the imitating 

 are good food, and would become exterminated but for the pro- 

 tection they obtain by being lost in the crowd of those they 

 resemble. I will confine my exhibits to butterflies, with which 

 I am most familiar, and whose structural characters and habits 

 I have studied for years. There are butterflies that, by many 

 experiments, have been found to be good food, and to be greedily 

 devoured by birds and lizards, and such creatures as prey on 

 them ; and are protected by their resemblance to others that, 

 also by many experiments, have been proved to be of a 



