120 University of California Publications in Geology [Vol. 7 



The first specimen found was obtained by Lawrence C. 

 Baker in the Mohave Miocene of California in April, 1911. It 

 represents the lower jaw of a form showing characters near 

 those of both Parahippus and Archaeohippus. A fragmentary 

 upper jaw, evidently belonging to an animal of the same species 

 as that found by Mr. Baker, was discovered in the Mohave Beds 

 by J. P. Buwalda and H. C. Mourning in January, 1913. 



The second type of anchitheriine horse discovered is repre- 

 sented by a slab containing scattered parts of a skeleton obtained 

 in the region southeast of Walker Lake, Nevada, by Baker 

 and Buwalda in May, 1912. This specimen had previously been 

 seen by Mr. T. H. Buck of Mina, Nevada. It was through the 

 kindness of Mr. Buck that the slab was pointed out to Baker 

 and Buwalda. The writer wishes to express his thanks for the 

 kind assistance given by Mr. Buck in bringing the specimen to 

 the railway station for shipment. 



HYPOHIPPUS (DRYMOHIPPUSi) NEVADENSIS, n. sub-gen. and n. sp. 



Type specimen no. 21056, University of California Collections in Verte- 

 brate Palaeontology. From the Stewart Valley Miocene, twenty-four 

 miles northeast of Mina, Nevada. 



Characters much as in SypoMppus, but metaloph of milk molars not 

 connected with ectoloph. 



The type specimen consists of a small portion of the skull 

 with three milk molars, portions of all four limbs, and a number 

 of scattered fragments of other skeletal parts. The elements of 

 the limbs were in part connected. 



Skull and Dentition. — The greater portion of the skull had 

 been weathered away before the specimen was discovered. All 

 that remains consists of a portion of the lower region of the 

 cranium. Fortunately it was embedded in such a manner that it 

 faced into the rock, and only the roots of the teeth were damaged. 

 The portions of the cranium present show little of significance. 



The dentition (figs, la and lb) shows three well-preserved 

 cheek-teeth. The incisors are not present. The cheek-teeth rep- 

 resent the milk dentition with Dm 4 just coming into function. 

 They are referred to the milk dentition as they are relatively 

 narrower than P 2 to P 4 of nearly related forms. 

 1 dpvfios, wooded dell or glade; 'iwwos, horse. 



