A satisfactory and easily recognised distinction between the rhinoceroses of south-eastern Asia and the two African species is afforded by the circumstance that while in the former the hide is thrown into a number of deep folds dividing it into separate areas, in the latter these folds are more or less lacking, so that the skin is comparatively smooth like that of a pig. The shape of the skin-folds serves to distinguish the species forming the subject of the plate from the other one-horned Asiatic species. Among the distinctive features of the present animal may be noted the coif-like expansions of skin at the sides of the head, the large tubercles, recalling the heads of the rivets in an iron boiler, on the shoulders and hind-quarters, and the somewhat triangular shape of the great shield on each shoulder, the fold forming the upper border of which does not extend across the back. By the older naturalists, rhinoceroses, elephants, and hippopotamuses were grouped together under the title of pachyderms,--a name which has completely dropped out of use in natural history. And very rightly, since the three groups of animals brigaded together under that designation have but little in common with one another. Elephants, for instance, form a group by themselves; hippopotamuses are cousins of the pigs, and thus related to deer and cattle; while rhinoceroses, together with tapirs and horses, form a third group by themselves. There may seem to the man in the street little in common between a great lumbering brute like a rhinoceros and a Derby winner; but the difference is due solely to the one being a modern specialised type cut out solely for speed, and the other an old-fashioned creature suited for wallowing in marshes or wandering on open plains where it is sufficiently protected by its size and ferocity. Take away the two side-toes from each foot of a rhinoceros, lengthen its limbs, lighten its head and body, modify to a comparatively slight degree its cheek-teeth, and replace its bare “pachydermatous” covering by a thinner, hairy skin, and we should have a horse. Fortunate it is for the naturalist that such primitive creatures as rhinoceroses and tapirs have survived to the present day to afford us an adequate idea of what their numerous extinct relatives looked like in life. Rhinoceroses are purely herbivorous animals, but whereas the great Indian species subsists chiefly on bamboo-leaves and other grasses, its two Asiatic relatives depend more upon boughs and roots; this difference being correlated with the structure of their teeth. Producing but one offspring at a time, and that at long intervals, these animals apparently live to a very great age, although by no means so long as elephants. The idea that the hide of the Indian species is bullet proof is altogether erroneous. THE BISON (_Bos [Bison] bonasus_)