524 UNGULATES. 



be either three or four in the hind-foot. The fore-foot is broader than the hinder 

 one, and generally has five nails. 



In most cases the males, and sometimes the females also, have a pair of tusks 

 in the upper jaw ; these tusks corresponding to one of the pairs of incisors of other 

 mammals, and not to the tusks of the wild boar and hippopotamus, which are 

 canines. There are no other front teeth in the upper, and none at all in the lower 

 jaw of the living species. The eyes are small in proportion to the size of the head ; 

 the tail is nearly cylindrical, and of considerable length, with a tuft of bristlj- hairs 

 at the end ; but the skin is nearly naked in the two existing species. The female 

 has a single pair of teats placed between the fore-legs. 



In addition to the proportions and position of the bones of the limbs already 

 referred to, it may be observed in connection with the skeleton that the two bones 

 of the lower segment of each leg are perfectly distinct from one another ; and that 

 in the ankle the huckle-bone, or astragalus, is nearly flat both above and below, 

 and is of slight vertical thickness, but of great horizontal extent. The vertebrae of 

 the back have very tall spines for the attachment of the powerful ligaments nece* 

 sary to support the enormous weight of the head ; and the ribs are of great length, 

 and thus afford ample space for the viscera. It will be noticed in the figure of the 

 skeleton that the blade-bone, or scapula, has a backwardly recurved process pro- 

 jecting from its space ; and it is remarkable that a nearly similar condition of this 

 acromial process is found in the Rodents. 



From the enormous size of the skull it might be inferred that 

 Skull 



elephants have very large brains. This, however, is far from the 



case, the brain not only being very small in proportion to the size of the animal, 



but likewise of a low degree of organisation. The brain of an elephant occupies 



indeed only a comparatively small portion of the space lying between the socket 



of the eye and the region where the vertebras of the neck articulate with the .skull. 



The whole of the elevated upper portion of the skull is occupied by a mass of bone, 



honeycombed into cells, and thus affords space for the attachment of the huge 



muscles of the jaws, and forms an adequate support for the trunk without unduly 



adding to the weight ; the great size of this region being also essential in order to 



harmonise with the immense development of the lower part of the skull, which has 



to accommodate the enormous tusks and molar teeth. Similar cells also enter into 



the structure of the hinder and basal region of the skull. There are many other 



peculiarities in the conformation of the elephant's skull, but it must suffice to 



mention here that the nasal aperture is situated high up in the front of the face, 



and that the nasal bones are reduced to mere triangular nodules, instead of having 



the elongated form characteristic of most mammals. 



Of the teeth a more detailed notice is necessary, since these afford 



some of the most essential characteristics of the group. As already 



mentioned, elephants have no canine teeth in either jaw ; while in the living species 



the tusks are developed only in the upper jaw. In the young elephant there is a 



minute pair of milk-tusks, which are shed at a very early age. The permanent 



tusks, which are nearly cylindrical in section, and taper to their extremities, 



continue to grow throughout the life of their owners, and thus remain permanently 



open at their bases, which are enclosed in sheaths of the premaxillary bones extend- 



