LOPHIODONTID^. 627 



oblique. Neural spinal low. The centra of the dorsals are weakly opis- 

 thocoelous. On these vertebrae the interspinous foramina are never cut off 

 from the interspinous intervals, as is the case in Tapirus. Except on the 

 first two or three dorsals, the prezygapophyses are flat or convex surfaces 

 directed downward and forward, and not recurved posteriorly or laterally, 

 and separated on the median line by a notch. The neural spines are high, 

 and the diapophyses are short. On the posterior dorsals anterior meta- 

 pophyses are developed, and the tubercular facets are nearly sessile on their 

 external sides. The metapophyses are separated by a groove from the 

 prezygapophyses. The former send a ridge downward and backward on 

 the last dorsals. On the lumbars the prezygapophyses embi-ace the post- 

 zygapophyses laterally, but do not embrace them in the manner character- 

 istic of the Ruminantia. A diapophysial i-idge appears and becomes promi- 

 nent, its base extending the entire length of the centrum. 



The axis of this genus is that of a primitive ungulate of any type, 

 and would even pass for that of a carnivore. The later cervicals are 

 characteristically ungulate, but the further subdivision is not indicated. The 

 remaining parts of the column show decided indications of equine i-ather 

 than tapiroid affinity, in two points. These are : first, the absence of iso- 

 lated interspinous foramina ; second, the narrow form and more revolute 

 articular surfaces of the postzygapophyses. 



The scapula has a well-developed incurved coracoid process, resem- 

 bling in this respect Corypliodon and Anchithermm, and difi"ering from recent 

 Perissodadyla. 



Both tuberosities of the humerus are well developed, and inclose a 

 simple bicipital groove, as in Tapirus and Anchitherium, having no trace of 

 the additional groove seen in the later equine types. The condyles are 

 characterized by the presence of a prominent intertrochlear crest, and by 

 the fact that the condylar surface external to it, does not extend all the 

 way on the posterior aspect. There are no epicondyles. The ulna and 

 radius are distinct. The fomier is slender, most so distally ; the radius 

 maintains its proportions throughout. Its head is a transverse oval, with- 

 out interlocking angle below. The carpal svirface of the ulna is simple, 

 that is, without dividing ridges. 



