150 STUDIES IN THE EVOLUTION OF ANIMALS 



was ancestrally a big central plate is now in the rosette of the 

 Jaguar a brown patch ; and what were the encircling platelets are 

 now black spots^ or a fusion of them forming a black ring, the whole 

 rosette being of a different colour from the general fawn colour of 

 the inter-rosette spaces. These three distinct colorations, well 

 marked in the Ocelots, suggest atomic localised differences in the 

 nerve-centres of which at present we know nothing. 



Why in the Cats the spots are black, and in the Deer they are 

 white, I am unable to say. I find it also impossible to determine 

 whether the grey dappled Horse is an albinoid variation of the 

 brown dappled Horse, or the latter is a melanoid variation of the 

 former. I must leave such questions for others to answer who 

 may know more about the matter than I do. 



All I am here concerned with is, that there is in many animals 

 a sharp line of demarcation between the colouring of the back and 

 that of the abdomen, and this I attribute to ancestral differences of 

 armoured and unarmoured surfaces. 



No one who is imbued with the principle of evolution can 

 contemplate the skin of the Jaguar in Fig. 4 without saying, 

 Yes ; the whole thing is a picture of armour-plating. This is not, 

 however, all, for that skin, in the different mode of resetting be- 

 tween the dorsal and the ventral surfaces, and in the difference of 

 general coloration between the upper and lower parts, gives also 

 evidence, at least to my mind, that the lower lost their armour 

 before the upper parts. 



This theory does not attempt to account for the variations of 

 nerve-centres. Those must be relegated to congenital causes we 

 do not yet sufficiently understand, and perhaps to the action of the 

 environment. 



In another part I shall endeavour to show that armoured 

 mammals must have been originally and ancestrally armoured all 



