TEGUMENTARY STRUCTURES n 



Lion accords well with the prevailing tint of its native desert ; and 

 any one who has seen an Elephant or Buffalo in the dee}) shades of 

 an Indian forest will realise how perfectly adapted is their dull, 

 slaty colour to concealment in such a spot. The dun colour of the 

 Wild Ass of India is equally well suited to the sandy deserts of 

 Kutch ; it is also stated that the brilliant stripes of the Zebras of 

 Africa are arranged in such proportion as exactly to match the pale 

 tint which arid ground possesses when seen by moonlight. 1 The 

 most remarkable instance of protective coloration is, however, to be 

 found in the Sloths of South America, in which the coarse gray 

 hairs so closely resemble a mass of lichenous growth that it is 

 almost impossible to distinguish these animals when at rest from 

 the gnarled and lichen-clad boughs from which they suspend them- 

 selves. This resemblance is increased by the fact that the hairs 

 actually develop a growth of lichens upon themselves. That the 

 sombre coloration of these animals has been produced to harmonise 

 with their present surroundings seems to be evident by the circum- 

 stance that when the long hair is plucked off the under fur is seen 

 to present a bold alternation of black and yellow stripes, which 

 may probably be regarded as the original primitive coloration of 

 this group. 



Scales, etc. — True scales, or flat imbricated plates of horny 

 material, covering the greater part of the body, so frequently 

 occurring in reptiles, are found only in one family of mammals, the 

 Manidxe or Pangolins ; but these are also associated with hairs 

 growing from the intervals between the scales, or on the parts of 

 the skin not covered by them. Similarly, imbricated epidermic 

 productions form the covering of the under surface of the tail of 

 the flying Eodents of the genus Anomalurus ; and flat scutes, with 

 the edges in apposition, and not overlaid, clothe both surfaces of 

 the tail of the Beaver, Rats, and others of the same order, and also 

 of some Insectivores and Marsupials. The Armadillos alone have 

 an ossified exoskeleton, composed of plates of true bony tissue, 

 developed in the derm or corium, and covered with scutes of horny 

 epidermis. Other epidermic appendages are the horns of Ruminants 

 and Rhinoceroses, — the former being elongated, tapering, hollow 

 caps of hardened epidermis of fibrillated structure, fitting on and 

 growing from conical projections of the frontal bone, and always 

 arranged in pairs, while the latter are of similar structure, but 

 solid and without any internal bony support, and (in all existing 

 species) situated in the median line. Callosities, or bare patches 

 covered with hardened and thickened epidermis, are found covering 

 the pads under the soles of the feet and undersurfaces of the 

 toes of nearly all mammals, upon the ischial tuberosities of many 

 Apes, the sternum of Camels, on the inner side of the limbs of the 



1 Galton's South Africa, p. 187. 



