CHAP. XVII.] 



MAMMALIA. 



211 



Maryland to Florida ; and an extinct genus, Frorastomus, in some 

 Tertiary deposits in the Island of Jamaica. 



In Post-pliocene deposits in Siberia, remains of Bytina have 

 been found ; while several species of the extinct genus Halt, 

 therium, perhaps intermediate between Manatus and Halicore, 

 have been found in the older Pliocene and Upper Miocene of 

 France and Germany. 



Order VII.— UNGULATA. 

 Family 43.— EQUID^. (1 Genus, 8 Species.) 



The Horses, Asses, and Zebras form a highly specialized group 

 now oonfined to the Ethiopian and Palsearctic regions, but during 

 the middle and later tertiaries having a very extensive range. 

 The zebras (3 species) inhabit the greater part of the Ethiopian 

 region, while the asses (4 species) are characteristic of the deserts 

 of the Palsearctic region from North Africa and Syria to Western 

 India, Mongolia, and Manchuria. The domestic horse is not 

 known in a wild state, but its remains are found in recent de- 

 posits from Britain to the Altai Mountains, so that its disappear- 

 ance is probably due to human agency. 



Extinct Uquidce. — Extinct forms of this family are very 

 numerous. The genus Equus occurs in Post-pliocene and Plio- 

 cene deposits in Europe, North America, and South America. 

 In North America the species are most numerous. An allied 

 genus Hipparion, having rudimentary lateral toes, is represented 



