570 



University of California Publications in Geology [ VoL - 11 



and much more slender than in Equus. It closely resembles the prox- 

 imal phalanges of Pliohippus pernix, the type of the genus Pliohippus. 

 It is somewhat more slender and much larger than the corresponding 

 element in Neohipparion whitneyi. Whether the specimen is to be 



referred to Hipparion, Neohip- 

 parion, or Pliohippus is uncer- 

 tain, but the relation to Plioh ippus 

 seems close. 



^ 202 



Fig. 200. Pliohippus?, sp. Third 

 metatarsal, no. 21201, X %. Ric- 

 ardo Pliocene, Mohave Desert, Cali- 

 fornia. 



Fig. 201. Pliohippus? , sp. Fourth 

 metatarsal?, no. 21480, X Ric- 

 ardo Pliocene, Mohave Desert, Cali- 

 fornia. 



Fig. 202. Pliohippus?, sp. Dis- 

 tal end of third metapodial, no. 

 21478, X y 2 . Ricardo Pliocene, 

 Mohave Desert, California. 



In no. 21197 (fig. 196) the prox- 

 imal phalangeal element is shorter 

 and much less slender than in no. 

 21200. It is also larger than in 

 any of the forms like Protohippus 

 or Meryehippus from the Barstow 

 beds, and is relatively wider than 

 the Barstow forms. This element 

 is nearer the form of the corre- 

 sponding element in Hypohippus, 

 but is longer and more slender 

 than any proximal phalanx of 

 Hypohippus known to the writer, 

 and much more slender than ele- 

 ments from the Barstow fauna 

 which are apparently to be re- 

 ferred to Hypohippus (see figs. 29, 

 30 ) . This element is near the form 

 of the proximal phalanx in Hip- 

 parion theoboldi of the Siwalik 

 beds, but is more slender and 

 smaller than in H. theoboldi. 



Several metapodials represent a 

 species much larger than any form 

 from the Barstow. A second and 

 somewhat smaller form is possibly 

 represented by a single specimen, 

 no. 21201. The distal end of a 

 202), represents a form possibly 



single metapodial, no. 21478 (fig. 

 larger and distinct from the others. 



In the more common form the shaft of metapodial III is consider- 

 ably larger than in any specimen from the Barstow beds, and is much 

 heavier than in the average Meryehippus or Protohippus species. 



