TEGUMENTARY STRUCTURES II 
Lion accords well with the prevailing tint of its native desert ; and 
any one who has seen an Elephant or Buffalo in the deep 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 
Mande 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 Rodents 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. 
