The Mammals of the Miocene are very numerous, and only the more important forms can be here alluded to.  Amongst the Marsupials, the Old World still continued to possess species of Opossum (Didephys), allied to the existing American forms.  The Edentates (Sloths, Armadillos, and Ant-eaters), at the present day mainly South American, are represented by two large European forms.  One of these is the large Macrotherium giganteum of the Upper Miocene of Gers in Southern France, which appears to hare been in many respects allied to the existing Scaly Ant-eaters or Pangolins, at the same time that the disproportionately long fore-limbs would indicate that it possessed the climbing habits of the Sloths.  The other is the still more gigantic Ancylotherium Pentelici of the Upper Miocene of Pikerme, which seems to have been as large as, or larger than, the Rhinoceros, and which must have been terrestrial in its habits.  This conclusion is further borne out by the comparative equality of length which subsists between the fore and hind limbs, and is not affected by the curvature and crookedness of the claws, this latter feature being well marked in such existing terrestrial Edentates as the Great Ant-eater.

[Illustration:  Fig. 242.—­Front portion of the skeleton of Andrias Scheuchzeri, a Giant Salamander from the Miocene Tertiary of Oeningen, in Switzerland.  Reduced in size.]

The aquatic Sirenians and Cetaceans are represented in Miocene times by various forms of no special importance.  Amongst the former, the previously existing genus Halitherium continued to survive, and amongst the latter we meet with remains of Dolphins and of Whales of the “Zeuglodont” family.  We may also note here the first appearance of true “Whalebone Whales,” two species of which, resembling the living “Right Whale” of Arctic seas, and belonging to the same genus (Baloena), have been detected in the Miocene beds of North America.

The great order of the Ungulates or Hoofed Quadrupeds is very largely developed in strata of Miocene age, various new types of this group making their appearance here for the first time, whilst some of the characteristic genera of the preceding period are still represented under new shapes.  Amongst the Odd-toed or “Perissodactyle” Ungulates, we meet for the first time with representatives of the family Rhinoceridoe comprising only the existing Rhinoceroses.  In India in the Upper Miocene beds of the Siwalik Hills, and in North America, several species of Rhinoceros have been detected, agreeing with the existing forms in possessing three toes to each foot, and in having one or two solid fibrous “horns” carried upon the front of the head.  On the other hand, the forms of this group which distinguish the Miocene deposits of Europe appear to have been for the most part hornless, and to have resembled the Tapirs in having three-toed hind-feet, but four-toed fore-feet.