THE HOOFED MAMMALS. 119 



normally present in the males, and often in both sexes. Their huge and 

 massive limbs are less enveloped superiorly in the skin of the body than 

 is the case with the great majority of Ungulates; and their component long- 

 bones are remarkable in being placed almost vertically one 

 above the other, so as to form straight columns for the The Elephants. 

 support of the body. From all other living members of the Family 

 order elephants differ in having five perfect toes to each foot ; Elephantidce. 

 while they are further distinguished from all, except the little 

 hyraces, by the arrangement of the bones of the wrist-joint in the fore-foot. 

 In this joint the two horizontal series of quadrangular bones are placed 

 almost directly over one another, and likewise above the supporting meta- 

 carpal bones, in such a manner that the whole foot could be completely 

 cleft in twain between the third and fourth toes. The rounded feet are 

 supported on large, flat cushions, on the front edge of which the position 

 of the toes is indicated by large, broad nails. As regards the teeth, the 

 upper tusks correspond to one of the three pairs of incisors characterising 

 more typical Mammals ; but there are no other incisors, nor any traces of 

 canines. The tusks always remain open at the base, and grow continuously 

 throughout the life of their owners. The cheek teeth, of which there are 

 six pairs in each jaw, are peculiar in that they are not all in use at the same 

 time, the small anterior ones coming into use first, and being in turn shed 

 as they are worn out and replaced by the larger hinder ones, which make 

 their appearance in the jaws in an arc of a circle, so that very old individuals 

 are left with only a single huge molar on each side of each jaw. Equally 

 peculiar are these teeth in structure. They consist of a great number of tall, 

 parallel, thin, transverse plates growing from a common base, and consisting 

 of a core of comparatively soft ivory, covered with a thin layer of flint-like 

 enamel ; the interspaces, or valleys, left between the plates being filled up 

 with a still softer substance known as cement. When such a tooth is worn 

 by grinding against its fellow in the opposite jaw, the summits of the enamel- 

 covered plates are cut through so as to expose elongated ellipses of ivory ; 

 and the roughened, flat surface thus produced is made of vertical transverse 

 layers of three substances, arranged in the order of cement, enamel, ivory, 

 enamel, cement. Since each of these constituents differs in hardness, it will 

 be sufficiently apparent that the millstone-like apparatus formed by the teeth 

 is admirably adapted for triturating vegetable substances of all kinds to a 

 pulp. 



Of the two existing species, the Indian elephant (E. indicus) is best dis- 

 tinguished by the structure of the molar teeth, in which the constituent plates 

 are very numerous and very thin, with their investing enamel, which is also 

 thin, thrown into a number of fine crimpings. Tusks are usually present in 

 the male sex only, and may even be wanting in that. The ears are relatively 

 small ; and the finger-like process on the upper margin of the tip of the 

 trunk is much more developed than the one on the lower edge. As a rule, 

 there aro four nails on the hind-foot, and five on the front. The Indian 

 elephant is an inhabitant not only of the country from which it takes its 

 name, but likewise of Ceylon, Burma, the Malay Peninsula, Cochin-China, 

 Sumatra, and Borneo, although it may have been introduced into the island 

 last named. Associating in herds of variable size, it is fond of cool, shady 

 forests in the neighbourhood of water, avoiding as much as possible the full 

 glare of the sun, and feeding chiefly upon leaves, fruits, and small branches. 

 So much has been written on the subject of the habits of this species that this 



