1919] Merriam: Tertiary Mammalian Faunas of Mohave Desert 491 



degree of cementation suggests Protohippus. The premolars forming 

 in the jaw are large and might represent either M. c. stijlodontus or 

 M. intermontanus. 



Fig. 54. Merychippus intermontanus? Merriam. Superior milk dentition with 

 occlusal view of M 1 , no. 21460, natural size. Barstow Miocene, Mohave Desert, 

 California. 



Fig. 55. Merychippus intermontanus Merriam. Inferior milk dentition with 

 permanent M 1( no. 21398, natural size. Barstow Miocene, Mohave Desert, Cali- 

 fornia. 



Fig. 56. Merychippus intermontanus Merriam. Dm 3 , no. 21461, natural size. 

 Barstow Miocene, Mohave Desert, California. 



In no. 21460 the upper milk molars (fig. 54) are somewhat larger 

 than in no. 19816 though of much the same form. In no. 21460 the 

 slightly worn crowns are high and well cemented. They seem as 

 advanced as in Protohippus. In no. 21460 M l is a large tooth com- 

 parable in general to M 1 of M. intermontanus, and it is not improbable 



