698 MAMMALIA [CH. 



Roe-deer, Capreolus capraea ; the Fallow-deer, G. dama, is probably 

 an introduced species, and at present is only represented in Britain 

 by semi-domesticated animals. In Roman times there were wild 

 Oxen, and some suppose that a breed of wild Oxen kept at Chilling- 

 ham in Northumberland and in one or two other large parks are 

 descended from these ancestors. 



In Canada a large variety of the Red- deer, the "Wapiti, Cervus 

 canadensis, is found, also the Reindeer or Caribou, Rangifer 

 tarandus, and the Elk or Moose, Alces machlis, with short bull-like 

 neck and broad fan-like horns. Throughout the whole of Eastern 

 America the so-called "Red-deer," Cariacus virginianus, is found in 

 the mountains. The Bovidae are represented by the Musk-ox, Ovibos 

 moschatus, with horns curved like a ram, and by the Rocky Mountain 

 Goat, Hapkceros montanus. Until recently the American Bison, the 

 so-called "Buffalo," Bison americanus, ranged in enormous herds over 

 the Western plains of North America ; but before 1883, with the 

 exception of a few scattered stragglers which are "protected," this 

 magnificent animal had been exterminated. 



Until the introduction of modern fire-arms the Artiodactyla were 

 in their way as successful and rapidly evolving a group as Teleostean 

 Fish or as Birds. In a comparatively short time, however, all except 

 the domesticated breeds or species specially preserved for sport will 

 be exterminated. As it has been discovered that they harbour in 

 their blood the dreaded parasite which causes sleeping-sickness it is 

 probable that in regions infested by this disease their preservation 

 for purposes of sport will be of short duration. In Tertiary rocks 

 numerous families of extinct Ungulates are found which completely 

 fill the gaps existing between Suidae and Tragulidae on the one 

 hand and Traerulidae and Bovidae on the other. 



Order VII. Sirenia. 



The Sirenia or Sea-cows agree with the Cetacea or Whales in 

 the manner in which they are adapted to an aquatic life. Thus all 

 trace of hind-limbs has been lost, a pair of bones representing the 

 pelvic girdle alone remaining, the fore-limbs have become flippers, 

 'the tail is broadened and there is a tail fin with horizontal flukes. 

 Underneath the skin there is a thick layer of fat and the hairy coat 

 is reduced to a few scanty hairs scattered over the skin. The lips, 

 however, are covered with numerous thick bristles. The nasal organ 

 is rudimentary. Apart from these resemblances which are due to 



