98 ORIGIN, ETC., OF THE FAUNA. 
conclusion that Mazama, typically a South American genus, is a more primitive type, 
unless it be degenerate, in its simple one-spiked antlers. Nevertheless, the absence of 
extinct Deer in South America, except in late Tertiary (Pleistocene) deposits, precludes 
at present the view that the family was evolved in that country and subsequently made 
its way northwards. 
The Antilocapride are not certainly known from deposits in North America older 
than the Pleistocene, and none have been discovered elsewhere. Possibly the North 
American mid-Miocene genus Dromomeryx was the ancestral form. 
The oldest-known forms of Caprine (Ovis) and Bovine (Bison) are European. 
The Bovinze do not appear to be definably distinct from the so-called Tragelaphine 
Antelopes, which in Europe go back to the Upper Miocene. A Caprine (Cridotherium) 
is of that date also. Hence it appears that the Artiodactyle Ungulates of Central 
America must be regarded as of northern descent. 
Order PERISSODACTYLA. 
Of the existing families of this order only the Tapiride occur in Central America, 
where they are represented by two species of the genus Tapirella (Elasmognathus), 
namely bairdi, ranging from South Mexico to Panama, and dow?, from Guatemala to 
Nicaragua and Qosta Rica. The Tapirs of South America, where they extend from 
Venezuela to the Northern Argentine, are referred to a distinct genus, Zapirus. 
Outside Tropical America the family contains but one representative, namely, Rhzno- 
chorus indicus, from the Malay Peninsula and Sumatra. 
Tapirs referred to a variety of genera inhabited North America from the Lower 
Eocene and Europe from the Lower Oligocene. ‘There are gaps in the genealogy of 
the recent forms, but species akin to them have been discovered in Pliocene deposits in 
Europe and Asia and possibly in contemporaneous bedsin North America. From this 
it seems tolerably clear that the existing genera are the survivors in the East Indies 
and in Tropical America of a family formerly widely distributed in the Northern 
Hemisphere. 
Order SIRENIA. 
One genus of this order, the Manatee (Zrichechus = Manatus), occurs in the rivers 
of eastern Central America and South America. It also inhabits some of the rivers of 
Western Africa, but is not found elsewhere. 
‘There is evidence that the Sirenia were evolved in North Africa from the stock that 
also gave rise to the Proboscidea. Genera of Eocene age have been discovered in 
Egypt and also in the West Indies. Although Zrichecus itself is only known as an 
existing genus, its presence in rivers and estuaries on the eastern and western shores 
of the Atlantic and its avoidance of the open sea have been cited as evidence of a 
continuous coast-line between Africa and Tropical America. 
