i68 THE COURTSHIP OF ANIMALS 



doubt but that " Natural Selection " was the agent which 

 had determined their elaborations for protective purposes, 

 and in such and similar cases this may be largely true. 

 But the material which " Natural Selection " has worked 

 upon has been furnished by the secretions of the sexual 

 glands to which reference has so frequently been made 

 already. These seem to possess a very marked tendency 

 to contain an excitant which promotes the formation of 

 intense pigmentation, or an excess of tissue which may 

 assume the form of weapons of offence, or of ex- 

 crescences in the form of spines, or other ornamental 

 features. Animals in whom this tendency to pigmenta- 

 tion and ornament has developed must, so to speak, 

 obtain a licence from " Natural Selection " if they are 

 to retain it. That is to say, if such ornament when- 

 ever it appears makes the wearer conspicuous to its 

 enemies, or hampers it in escaping therefrom, or in 

 fulfilling the ordinary avocations of life, then its 

 further progress will be inhibited, or the wearer will 

 be exterminated. But the tendency to produce colour, 

 a by-product of the sexual gland secretions, may inci- 

 dentally serve to afford it a protective garb, and in 

 this event its further elaboration in the required 

 direction is assured. 



In certain abnormal, sexually poisoned individuals 

 among the human race it is well known pleasure is derived 

 from flagellation. There is but one instance known to 

 me where this obtains as a normal accompaniment of 

 desire among the lower animals, and this occurs in one of 

 the Painted Terrapins {Chrysemys pictd), whose finger- 

 nails are produced into long, whip-like ends. I had the 

 good fortune to witness their use one day when in the 

 Reptile House at the Zoological Gardens in London. 



