196 STUDIES IN THE EVOLUTION OF ANIMALS 



animals which are armoured above and below ; animals which 

 are armoured only above ; animals which are spotted above and 

 below ; animals which are spotted only above ; others which are 

 darker above and lighter below, with modifications in other parts ; 

 and finally animals which have lost every trace of ancestral armour, 

 and have become self-coloured throughout. 



All these changes on the surfaces, it would appear, have their 

 * molecular equivalents ' in the nerve-centres ; and when modifica- 

 tions, from whatever cause, occur in these, their representatives 

 on the surface undergo a simultaneous modification. 



What wonder is it that some sort of picture of bygone states 

 should now be produced, when we know that every sensory im- 

 pression leaves a record in the grey matter which we call memory ? 



Now how did natural selection come in, in the case of Jaguars 

 and Leopards ? These carnivora are expert climbers and pass 

 a part of their life on trees. Their skin-rosetting harmonises 

 well with the surrounding lights and shades thrown by the foliage, 

 and so this curious coloration has been maintained by natural 

 selection, and not made by it, while in the case of the adult Puma 

 and Lion the same process may have selected away the picture- 

 rosettes. 



Of course the surviving Leopards that frequented trees did 

 not go there because they thought the lights and shades of the 

 leaves would protect them. They frequented trees for other 

 purposes, and found that there they were protected that is, 

 there they could secure prey more easily than on the plain or 

 among bushes ; and so the Cats with these peculiar markings 

 have been preserved. However undeveloped the brain of a wild 

 or domestic animal may be, it knows very well where it can 

 get food easily. 



To try to account for every bit of coloration in existing 



