1913] 



Mcrriam: New Anchithcriine Horses 



427 



clearly distinguished from that genus. Viewed from the most 

 unfavorable angle, the gap between this form and typical Hypo- 

 hippus seems less than the spaces between other anehitheriine 

 genera. The writer has therefore tentatively included this species 

 in the Hypohippus group, with the suggestion of incipient 

 separation indicated in the subgeneric distinction. The new sub- 

 genus, Drymohippus, proposed to include this form, bears the 

 characters of Hypohippus excepting in the separation of metaloph 

 and ectoloph in the milk dentition. Later investigations may 

 add other distinctive characters. 



PARAHIPPUS( ?) MOURNINGI,s n. sp. 



Type specimen no. 19840, a portion of a maxillary with milk dentition 

 and M 1 . Paratype, a portion of a mandible, no. 19764, with dentition 

 representing P 2 to 1vl 2 . Both specimens from the Mohave Miocene, Mohave 

 Desert, California. 



A portion of a lower jaw with dentition (figs. 5a and 5b) 

 obtained by Mr. Baker in 1911 was recognized by the writer as 

 representing a horse with characters near Parahippus and Hypo- 

 hippus, but with size and stage of evolution suggesting Archaeo- 

 hippus. The specimen differed, however, from the only lower 

 jaw material referred to Archaeohippus in several characters, 

 and especially in the absence of the strong internal cingulum 

 shown on teeth referred to Archaeohippus by Gidley. 4 In 

 January, 1913, a second specimen, a maxillary (fig. 3) with Dm 3 

 Dm 4 , and M 1 , representing a very small brachyodont horse, was 

 obtained in the Mohave region by Buwalda and Mourning, and 

 again the resemblance to the genera Parahippus, Hypohippus, 

 and Archaeohippus appeared. An approximation of the dimen- 

 sions of the cheek-tooth series, as well as a comparison of 

 individual teeth, shows that the upper and lower jaw specimens 

 represent animals of very nearly the same size. The simi- 

 larity of dimensions, considered with similarity of relationship 

 to other forms and similarity of occurrence, leaves little room 



3 This species is named in honor of Mr. II. S. Mourning, through whom 

 the first specimens from the Mohave region came into the writer's hands. 

 i Gidley, J. W., Bull. Amer. Mus. Nat. Hist., vol. 22, p. 385, 1906. 



