152 



UNGULATA 



ORDER VII 



cheek teeth composed of a W-shaped ectoloph, two robust internal cones, and 

 two independently developed intermediate tubercles ; also with an accessory in- 

 termediate tubercle on the posterior border and hypostyle. The two V-shaped 

 crescents of the inferior cheek teeth form at their 

 union an indistinctly bicuspidate internal pillar. 

 Manus and pes tridactyl, lateral metapodials slender, 

 their toes scarcely reaching the ground. In the fore- 

 foot a short splint or styloid vestige of the fifth 

 metacarpal is present. Oligocene (White River beds); 

 S. Dakota, Colorado. M. haircli Leidy sp. has the size 

 of a sheep. 



Miohippus Marsh. Larger than MesoMppus, upper 

 incisors with pits, cheek teeth very similar to those 

 of Mesohippus. M^ and heel of M.^ unreduced. Upper 

 Oligocene and Lower Miocene of North America. 

 M. anceps Marsh, equiceps Cope, condoni Leidy, from 

 John Day formation of Oregon ; M. intermedins, M. 

 validus Osborn, from Protoceras beds of South Dakota. 

 Anchitherium H. von Meyer (Fig. 207). With the 

 exception of the small first lower premolar, cheek teeth 

 homoeodont. Ectoloph of the superior molars and 

 premolars W-shaped. Internal cones robust, united 

 with the narrow intermediate tubercles and with the 

 ectoloph by oblique ridges ; accessory intermediate 

 SLtr'i!LeftSoot.'''i; hypostyle (Fig. 207, d') on the posterior border. 

 Left hind foot, i/s- (After Crowns of the incisors obliquely inclined inward, with 



Marsh ) . 



slightly depressed pits. Cheek teeth of the mandible 

 composed of two V-shaped crescents, which at their union form two internal 

 cusps distinct at the tip, connate below ; third molar with reduced third 

 lobe. Skull similar to that of Palaeotherium. Ulna tapering below and 

 fused with the radius at its slender distal 

 end. Scaphoid and lunar nearly as high 

 as broad, distally both resting on a very 

 broad magnum ; unciform narrow and long. 

 Second and fourth metacarpals scarcely 

 one-third as stout as the median one, but 

 little shorter, and bearing three weak 

 phalanges. Fibula extremely slight, styloid, 

 fused with the tibia. Pes tridactyl, lateral 

 metatarsals slender. 



The single European species, A. uureli- 

 anense Cuvier sp. ( = Palaeotherium hippoides 



Blainville), characterises the Upper Miocene of France, southern Germany 

 and Austria. One species, A. zitteli Schlosser, in the Pliocene of China. 



Hi/pohippus Leidy. With brachyodont, Anchitherium-like cheek teeth, 

 and lateral toes very similar. Middle Miocene ; Deep River beds, Montana. 

 H. {Anchitherium) equinus Scott. Upper Miocene ; H. affinis Leidy, E. matthewi 

 Barbour. Of larger size. 



Parahippus (Anchippus) Leidy (Fig. 208). Milk teeth, premolars and 

 molars higher than in Anchitherium. Crochet always present. Upper incisors 



Fig. 206. 

 Mesohippus celer Marsh. 



Fig. 207. 

 Anchitherium aurelianense Cu\ier sp. 

 Upper Miocene, Georgensgmiind, Bavaria. 

 A, Upper and B, lower molar, i/i. 



