86 



OSBORN: OLIGOCENE, MIOCENE, PLIOCENE EQUIDiE. 



m 1 2 rather 

 metaconule 



sharp and continuous; (3) protoconule small but well defined; (4) no crochet indicated on metaloph, in which 

 is very faintly indicated; (5) hypostyle moderately large, subtriangular; (6) parastyle small; (7) mesostyle 



sessile and thin; (8) faint ridges on paracone and metacone. (9) Limbs 

 elongate, metapodials unusually long and slender, metatarsals nearly the 

 same length as the radius; (10) ungual phalanges long and narrow; (11) 

 tibia nearly one-fourth longer than radius; (12) pes anisotridactylous. 



Douglass observes (p. 273) : " A remarkable characteristic of this horse 

 is the extreme length and slenderness of the limbs combined with the 

 primitive pattern of the teeth, which, with the exception of the somewhat 

 greater height of the different elements .... are scarcely more progressive, . . . 

 than are the teeth of some of the horses of the Lower Oligocene." 



Fig. 62. Original figures of parts of the type of Parahippus taxus Douglass, Carnegie Mus. 836. (3, 4) Right pes 

 (6, 7) crown and side views of deciduous premolars, also m 1-2 . (8) Skull. After Douglass, 1908, PI. lxvii. Skull and 

 limb bones one-half natural size, teeth natural size. 



Parahippus agrestis Leidy 1873. 

 Text Fig. 63. 



Anchitherium agreste, Leidy, Joseph. "Contributions to the Extinct Vertebrate Fauna of the Western Territories," Rept. U. S. 

 Geol. Sum. Terr., F. V. Hayden, Vol. I, Pt. I, 1873, pp. 251-252, PI. vii, figs. 16, 17. 



Horizon and locality. — (Leidy) " . . .imbedded in an indurated, gray, arenaceous marl,. . . derived from a lacustrine 

 Tertiary deposit on Red Rock Creek, one of the head branches of the Jefferson Fork of the Missouri River." Montana. 

 Type collected by F. V. Hayden, 1871. 



