206 MEMOIRS OF THE CARNEGIE MUSEUM. 
Subfamily MOROPODIN A‘ subfam. nov. 
Genus Moropus Marsh. 
Marsh, American Journal of Science and Arts, Ser. III, Vol. XIV, pp. 249-251 
(1877). 
Type: M. distans Marsh, I. c., p. 249. 
Type Specimens: Professor Marsh described three species in his paper, the first 
of which, M. distans, according to the accepted laws of nomenclature becomes 
the type of the genus. Unfortunately the type is extremely inadequate, 
consisting simply of a cuboid, codssified first and second phalanges, and 
median phalanx. The material, which is generically, but not specifically, 
determinable, without doubt pertained to an animal which was probably 
not more than half the size of Moropus elatus. (First figured by Peterson, 
American Naturalist; Vol. XLI, p. 735 (1907).) 
Location of Types: Peabody Museum of Natural History, Yale University, New 
Haven, Connecticut. (Casts of types in Carnegie Museum.) 
Geological Horizon: John Day Beds, Oregon (Miocene). 
In addition to M. distans Professor Marsh described two other species which 
he referred to the same genus, M. senex, from the John Day Beds, and M. elatus, 
which he attributed, as we now know in error, to “‘the Lower Pliocene of Nebraska.”’ 
The latter species, which came from the Lower Miocene of Nebraska, is the basis 
of the present paper, and the question of the geological horizon from which it 
came as well as its osteology will be taken up at length in succeeding pages. It 
suffices to say here that there is no evidence that M. elatus has been found else- 
where than in the Lower Harrison Beds of Nebraska (Lower Miocene). Other 
species have been found in later horizons. 
9 
GENERIC CHARACTERS: Dentition I= Gu é 2 molars longer than 
Sop 8 ay 
broad, hypsodont, their external walls, as in Nestoritheriwm, more nearly 
vertical than in Macrotheriwm and Chalicotherium, in which genera the external 
walls are bent inwardly so that in unworn molars they present a surface almost 
horizontal extending inwardly to the middle of the tooth; the vertical crests 
of the ectoloph sharp; skull long and relatively narrow; the anterior margin 
of the posterior nares on the median line well back of the posterior margin of 
the last molar; fore feet tetradactyl (fifth digit greatly reduced); trapezium 
present; Me. III longest; dorsal surface of metacarpals straight longitudinally, 
not concave longitudinally as in Nestoritheriwm; distal face of astragalus 
