328 STUDIES IN THE EVOLUTION OF ANIMALS 



{d) Many mammals which have lost all vestige of rosetting 

 have still retained vestiges of ancestral carapacing, that is, a 

 picture-vea\.\ge of dorsal armour and ventral tmannour, such as still 

 exist in Armadillos and Pangolins, and that the contrasts of colour 

 between the dorsal and ventral surfaces mean that the ventral 

 surface lost its armour earlier than the dorsal surface, and there- 

 fore its hair had time to differ in coloration from the dorsal surface 

 which lost its armour at a later period ; 



{e) The contrasts of colour that we see so frequently in' the 

 muzzle, round the eyes, on the hands and feet, of so many mammals 

 mean the same thing, viz., that those parts lost their armour before 

 the rest of the body, and had time to differ in coloration, after the 

 hair replaced the armour of those parts. Time, of course, has often 

 obliterated all these contrasts of coloration, and in many cases has 

 substituted a uniform self-colouring ; 



if) The Rhinoceros has passed through similar stages. The 

 Rhinoceros Sondaicus carries still the plates of its Armadilloid 

 ancestor, while the Indian Rhinoceros has vestiges of ancestral 

 calcareous plating in it? hide-knobs. In some cases the Indian 

 Rhinoceros is only partially knobbed, but Sir J. W. Flower^ gives 

 one of this species knobbed all over, taken from a photograph of an 

 animal living in the Zoological Society's Gardens ; 



{£) Judging from the very numerous mammals that are either 

 rosetted, or spotted, or striped, or have ringed tails, or have 

 contrasts of colour between the upper and lower surfaces, it seems 

 probable that all existing mammals, including marsupials, de- 

 scended from armoured ancestors ; 



(Ji) The callosities on the legs of the Equidce, and of some 

 ruminants, seem to be vestiges of leg glands secreting some 

 odoriferous substance which, smeared on long grass as the animals 



' The Horse, Fig. 9. 



