larger area than at present. The Musk-ox, in fact, in Post Tertiary times is known to have extended over the greater part of Europe, remains of it occurring abundantly in certain of the bone-caves of France. As already mentioned, high authorities regard the Musk-ox as being truly a large Sheep, and as being, therefore, referable to the Ovida.

CHAPTER XXXIX.

ORDERS OF MAMMALIA-Continued.

HYRACOIDEA AND PROBOSCIdea.

ORDER VII. HYRACOIDEA.—This is a very small order which has been constituted by Huxley for the reception of two or three little animals, which make up the single genus Hyrax. These have been usually placed in the immediate neighbourhood of the Rhinoceros, to which they have some decided affinities, and they are still retained by Owen in the section of the Perissodactyle Ungulates.

The order is distinguished by the following characters :There are no canine teeth, and the incisors of the upper jaw are long and curved, and grow from permanent pulps, as they do in the Rodents (such as the Beaver, Rat, &c.) The molar teeth are singularly like those of the Rhinoceros. According to Huxley, the dental formula of the aged animal is

The fore-feet are tetradactylous, the hind-feet tridactylous, and all the toes have rounded hoof-like nails, with the exception of the inner toes of the hind-feet, which have an obliquely-curved nail. There are no clavicles. The nose and ears are short, and the tail is represented by a mere tubercle.

The living species of Hyrax inhabit Syria, Palestine, and South Africa. No fossil representative of the order has as yet been discovered. The Hyracotherium of the Eocene Tertiary, however, received its name from its supposed affinities to the living Hyrax.

ORDER VIII. PROBOSCIDEA.-The eighth order of Mammals is that of the Proboscidea, comprising no other living animals

except the Elephants, but including also the extinct Mastodon and Deinotherium.

The order is characterised by the total absence of canine teeth; the molar teeth are few in number, large, and transversely ridged or tuberculate; incisors are always present, and grow from persistent pulps, constituting long tusks (fig. 359).

Fig. 359.-Skull of the Indian Elephant (Elephas Indicus). iTusk-like upper incisors; m Lower jaw, with grinding molars, but without incisors; n Nostrils, placed at the extremity of the proboscis.

In all the Elephants there are two of these tusk-like incisors in the upper jaw, and the lower jaw is without incisor teeth. In the Deinotherium this is reversed, there being two tusk-like lower incisors and no upper incisors. In the Mastodons, the incisors are usually developed in the upper jaw, and form tusks, as in the Elephants; but sometimes there are both upper and lower incisors, and both are tusk-like. The nose is prolonged into a cylindrical trunk, movable in every direction, highly sensitive, and terminating in a finger-like prehensile lobe (fig. 359). The nostrils are placed at the extremity of the proboscis. The feet are furnished with five toes each, but these are only partially indicated externally by the divisions of the hoof. The feet are furnished with a thick pad of integument, forming the

palms of the hand and the soles of the feet. There are no clavicles. The testes are abdominal throughout life. There are two teats, and these are placed upon the chest.

The order Proboscidea comprises the three genera, Elephas (with both living and extinct representatives), Mastodon, and Deinotherium, the two latter being extinct. The order came into existence in the Miocene period, in which it is represented by all these three genera. The genus Elephas comprises the living Asiatic and Indian Elephants. In all the Elephants, whether living or extinct, the "tusks" are formed by an enormous development of the upper incisors. The milk-tusks are early shed, and never attain any great size. The permanent tusks, however, grow from persistent pulps, attaining in old males an enormous size. The lower incisors are absent, and there are no other teeth in the jaws except the large molars, which are usually two in number on each side of each jaw. The molar teeth are of very large size, and are composed of a number of transverse plates of enamel united together by dentine. In the Indian Elephant the transverse ridges of enamel are narrow and undulating, whilst in the African Elephant they enclose lozenge-shaped intervals.

The surfaces of the molars are approximately flat, and the plates of enamel form patterns which are very characteristic of

Fig. 360.-Molar of the Mammoth (Elephas primigenius), upper jaw, right side, half natural size. Post-Pliocene. a Grinding surface; 6 Side view.

the different species. Subjoined are illustrations of the molars of three of the most important Post-Pliocene Elephants (figs. 360-362).

No Elephant has as yet been discovered in the Miocene deposits of Europe, but six species are known from strata of this age in India. In the Pliocene period, Europe possessed its Elephants, of which the most important is the Elephas antiquus (fig. 362). This is essentially a southern form, and is found in Pliocene strata in France and Italy. It survived the Glacial period, and is found abundantly in various PostPliocene deposits. It abounded in Post-Pliocene times chiefly in Southern Europe, south of the Alps and Pyrenees; and it is only on the northern edge of this area that its remains are found commingled with those of the Mammoth.

Fig. 362.-Molar tooth of Elephas antiquus. Penultimate molar, one-third or natural size. Post-Pliocene and Pliocene. (After Lyell.)

Of the Post-Pliocene Elephants by far the best-known and most important is the Mammoth (Elephas primigenius). This remarkable form (fig. 363) was essentially northern in its distribution, never passing south of a line drawn through the Pyrenees, the Alps, the northern shores of the Caspian, Lake Baikal, Kamschatka, and the Stanovi Mountains (Dawkins). It occurs in the præ-Glacial forest-bed of Cromer in Norfolk, survived the Glacial period, and is found abundantly in PostGlacial deposits in France, Germany, Britain, Russia in Europe, Asia, and North America, being often associated with the Rein

deer, Lemming, and Musk-ox. That it survived into the earlier portion of the human period is unquestionable, its remains having been found in a great number of instances associated

with implements of human manufacture; whilst in one instance a recognisable portrait of it has been discovered, carved on bone. From its great abundance in Siberia, it might have been safely inferred that the Mammoth was able to endure a much