484 THE AGE OF MAMMALS 



Rocky Mountains. These are the typical chamois (Rupicapra), the goral, 

 the takin, the serow, and finally the American misnamed 'goat.'^ 



Tapirs. — The tapir of the Megalonyx Zone {T. haysii) has been dis- 

 covered in Kentucky, Indiana, Mississippi, and South Carolina. This 

 species is apparently more robust than the existing South American tapir. 

 A someAvhat smaller animal, referred by Leidy to T. Americanus, is indis- 

 tinguishable in size and form from the living T. terrestris of Central and 

 South America. Its remains have been found in Texas, Louisiana, Missis- 

 sippi, South Carolina, Virginia, Ohio, Illinois, and California. The tapir 

 was undoubtedly one of the most characteristic animals of the Megalonyx 

 life zone, especially in the forests of eastern North America. It apparently 

 migrated to the South during the period of the Ovibos life zone. 



Horses. — As studied by Gidley ^ there were at least ten forms or 

 species of horses in different parts of the United States and Mexico in Pleis- 

 tocene times, distinguished by geographic distribution, by size, and by the 

 proportions of the body and skull, and by the characters of the upper grinding 

 teeth. The E. fraternus, found in the Ashley River, South Carolina, and 

 characteristic of the southern United States, is still imperfectly known ; it rep- 

 resents a very small horse, with teeth scarcely as large as those of the Mexican 

 donkey and of a very complex pattern. The E. complicatus, first found 

 near Natchez, Mississippi, belonging in the western, southern, and middle- 

 western states, is a well-known animal characterized by teeth as large as 

 those of the ordinary horse, but with a skeleton of intermediate size; the skull 

 is especially distinguished by its short muzzle, in which respect it resembles 

 that of an ass. From the Rock Creek Beds of western Texas comes the E. 

 semiplicatus, which in certain cranial characters, as well as in the size and 

 proportions of its teeth, seems to present a close relationship to the ass (E. 

 asinus). On the Staked Plains of central Texas has been found E. scotti 

 (see Fig. 14), intermediate in size between E. complicatus and E. pacificus, 

 with a long face, relatively large head, long body, short neck, resembling in 

 its proportions the quagga {E. burchelli). From southwestern Texas comes 

 also E. giganteus, the largest species of horse hitherto recorded, the teeth 

 exceeding those of the largest modern draught horses by more than one 

 third of the diameter of the latter. In contrast with this is the E. tau in 

 the valley of Mexico, the smallest true horse known in America, more diminu- 

 tive than any European species living or extinct. Associated with this in 

 the valley of Mexico is E. conversidens. 



The type of horse found in the Middle Pleistocene forested region of 

 eastern Pennsylvania is E. pectinatus, from the Port Kennedy Cave. On 

 the Pacific slope, Cahfornia, has been found E. occidentalis, with teeth of 



1 Grant, Madison, The Rocky Mountain Goat. N. Y. Zool. Soc. New York, 9th Ann. 

 Rept., 1904, pp. 2.30-261. 



2 Gidley, J. W., Tooth Characters and Revision of the North American Species of the 

 Genus Equus. Bull. Amer. Mus. Nat. Hist., Vol. XIV, Art. ix. May 31, 1901, pp. 91-141. 



