SUBORDER D ARTIODACTYLA 211 



Asia and Europe. In the Missouri region it was represented by a second 

 species, 0. priscus Eiitimeyer. 



Euceratheri'um Sinclair. Skull ox-like. Parietal bones displaced to the 

 vertical occipital surface. Horns compressed, far removed from the orbits, 

 with tips directed outwardly. Teeth moderately hypsodont. Pleistocene ; 

 California. E. colUnum Sinclair and Furlong. 



Preptoceras Furlong. Similar to Euceratherium. Horns circular in section. 

 Pleistocene of California. 



Subfamily 2. Boodontia Schlosser. 



Skull flat or arched, with or without lachrymal fossa and ethmoidal vacuity, rarely 

 with both. Parietal bones nearly ahvays entering considerably into the formation of 

 the cranial roof ; cranial axis more or less bent ; air-cavities either absent, or confined 

 to the base of the frontal appendages, or filling a large part of the cranial roof. 

 Horns usually arising near the orbits, only rarely removed far backward, as a rule 

 directed backward, simply curved, or spiral, tips often turned outward. Cross-section 

 of horns circular, more rarely elliptical or keeled. Molars brachyodont or hypsodont, 

 often with vertical costae on the external cusps of the superior molars and on the 

 internal cusps of those below. Basal pillars not rare, especially on superior molars. 

 All molars and premolars loith rugose enamel, often with much cement. 



The Boodontia embrace the Cephalophinae, the Pseudotraginae (known only . 

 in the fossil state), the Biibalidinae, Hippotraginae, Cervicaprinae, Tragelaphinae 

 and Bovinae. They all originate in forms having teeth very similar to those of 

 the deer, but characterised by somewhat deeper crowns. The Tragelaphinae and 

 Cephalophinae still remain in this condition ; the Bubalidinae, Hippotraginae and 

 Cervicaprinae are very similar to the Bovinae in the structure of their teeth, the 

 Bubalidinae being distinguished from the latter merely by the absence of basal 

 pillars. Reduction of the premolars occurs rarely. The originally flat elongated 

 skull becomes modified partly through the bending downward of the cranial axis 

 and partly through the change of position of the horns. The parietal bones are 

 thus pressed more and more backward and to the angles, so that they enter 

 only very slightly into the formation of the cranial roof (many Bubalidinae 

 and Bovinae) or become quite rudimentary [Bos and Bovinae). The difference 

 between the Bubcdidinae (heretofore always associated with antelopes), Hippo- 

 traginae and Cervicaprinae, as opposed to the Bovinae, consists in the fact that 

 aside from the nature of the horns they never attain more than part of the 

 specialisation characteristic of the Bovinae, either in the structure of the teeth 

 or in that of the skull. Only short proximal rudiments of the lateral digits 

 have been found, and these are entirely absent in the Bovinae. 



The Boodontia are an Old World stock, which probably branched off from 

 hornless Cervicornia in the Lower Miocene, and are represented in the Upper 

 Miocene of Europe by several forms not particularly well characterised, 

 described as ^^ Antilope" clavata, cristata and martiniana, with deer-like dentition, 

 together with the slightly hypsodont genus Protragocerus. The organisation of 

 these primitive forms permits them to be considered as ancestors of nearly all 

 later genera. 



Group 1. Cephalophinae. 

 Skull slightly arched ; cranial axis not bent downward ; lachrymal fossa large, 



