INTRODUCTION xxxi 



in past ages, and of all kinds and descriptions. The coloration of 

 the skin is not a thing that can be fossilised, and so one has to put 

 ' two and two together ' in order to discover an explanation for the 

 varied markings of the mammals of our day. We not infrequently 

 pass over the seeming, and go a-hunting after the obscure and the 

 unlikely. 



It seems to me that the organs of animals which receive and store 

 up impressions, which we call nerve-centres, are as much engaged 

 in influencing the form and coloration of the markings of the skin 

 as they are in moulding and modifying the skeleton and other 

 parts of the body. They are the controllers and regulators of the 

 whole life, not only of the individual but also of the race. And 

 the individuals forming a race were after all part and parcel of the 

 ancestral stock, and were at one time or other organically con- 

 nected with it. 



I do not, however, pretend in these pages to account for every 

 speck and coloured hair, but to give my view of what seems to have 

 been the genesis of spots and stripes in mammals, and of the 

 contrasted coloration we see in so many animals, which would 

 indicate some sort of plan of coloration. I do not enter into 

 the microscopy of the subject— into how pigment cells behave 

 in fishes, and other small animals which change their coloration 

 and spotting according to surroundings. We know that the 

 Leopard, the Tiger, the Zebra, and others do not do so, and there- 

 fore we have to account for the genesis of their more or less 

 permanent spots or stripes. My suggestion would appear to be a 

 ' vera causa ' of the markings of the Jaguar, the markings of all 

 other mammals, in cases where these exist, being only a modifica- 

 tion of such rosettes as those of the Jaguar, and its markings only 

 a modification of vastly more ancient conditions. 



One of the problems to be solved is — How came the rosettes on 



