THE’ MIOCENE PERIOD. 315 
the more important forms can be here alluded to. Amongst 
the JZarsupials, the Old World still continued to possess 
species of Opossum (Didephys), allied to the existing American 
forms. The /dentates (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 AZacro- 
therium giganteum of the Upper Miocene of Gers in Southern 
France, which appears to have 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 Axcylotherium Pentelict of the Upper 
Miocene of Pikermé, which seems to have been as large as, or 
larger than, the Rhinoceros, and which must have been terres- 
trial 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. 
The aquatic Sirenians and Cefaceans are represented in 
Miocene times by various forms of no special importance. 
Amongst the former, the previously existing genus Halithertum 
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 (Balena), 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 RAznocertde compris- 
ing 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. 
