274 Annals of the Carnegie Museum. 



Merychippus ? missouriensis sp. nov. 



(Plate LXVI; LXVII, figure 5; Plate LXVIII, figures i and 2.) 

 (Type No. 905, Carnegie Museum Catalogue of Vertebrate Fossils.) 

 The type of this species is a portion of a skull, a mandible, a radius, 

 two femora, two complete and two incomplete metapodials, also num- 

 erous fragments. These bones represent a young individual, which 

 was found in the upper Miocene formation (Loup Fork). These 

 beds form a part of the bluffs along the eastern side of the Missouri 

 River north of Confederate Creek and east of Winston in Montana. 

 The type was collected by Earl Douglass and Ray Roberts in 1902. 

 From the same locality, only a few feet away, a nearly complete hind 

 foot (No. 858) was obtained. This undoubtedly belongs to the same 

 species as the type, and the age of the two individuals was nearly the 

 same, as shown by corresponding portions of mandibles with teeth. 



Distinguishing Characters of the Type. — (1) Lachrymal fossa long 

 and moderately deep, (2) malar pit with steep posterior side, bounded 

 below by a thin shelf-like malo-maxillary ridge, (3) temporary molars 

 brachyodont or brachy-hypsodont, (4) permanent molars curved and 

 strongly hypsodont, (5) both series of teeth with a coating of cement 

 which is not very thick, (6) enamel-lakes simple with only one or 

 two simple enamel-folds on each, (7) protocone and hypocone later- 

 ally compressed, the former separate from the protoconule but having 

 an angular projection toward the latter, (8) first temporary lower 

 molar minute, (9) intermediate external conule on lower temporary 

 molars concave on the inside, more or less flattened on the outside, 

 (10) metapodial nearly ninety per cent, of the length of the radius 

 and eighty-four per cent, of the length of the femur exclusive of the 

 proximal epiphysis. 



Measurements. 



mm. 



Length of upper temporary molar series 84.2 



Length of DMI 13.7 



Length of DM^ 28 



Length of DM^ 22 



Width of DM3 2I5 



Length of DM± 21.5 



Length of Mi 22 



Width of Ml „ 21 



Length of M^ 21 



Length of mandible 260 



