658 THE BEIDGEE FAUNA. 



condyle pi'esenting superiorly; symphysis coossified. Postparietal and 

 postsquamosal foramina present; mastoid small, if present; supraglenoid, 

 none. 



Atlas with a vertebrai-terial canal perforating the base of the transverse 

 process from behind, and issuing on the inferior surface. The vertebral 

 artery then occupied a groove at the anterior base of the transverse process, 

 and entered the neural canal by a large foramen well posterior to the 

 occipital cotylus. Atlas and axis rather short; other cervicals more elon- 

 gate. Odontoid process very robust, and a little flattened above. Atlantal 

 facets well separated below. Other cervicals strongly opisthocoelons, and 

 with transverse processes which are well extended anteriorly and posteriorly 

 and but little transversely. The diapophysis and parapophysis are quite 

 distinct in the sixth cervical; the former lateral and subcylindric, the latter 

 flat and extended anteroposteriorly and directed downwards. The dorsal 

 vertebrae have well-developed metapophyses. Anteriorly they rise above 

 the diapophj^ses (tubercular articulations), and, as the latter diminish, stand 

 above the prezygapophyses and increase in elevation. The prezygapo- 

 physes of the lumbars embrace the postzygapophyses on the external side, 

 as in the Equidce; more than in the Tapiridoe, and much more than Rhi- 

 noceros. They resemble those of Hyracotlieriuin more than any of the types 

 named. The neural spines are well develojied on all the dorsal and lumbar 

 vertebrae. The interspinal foramina have no spinal foramina separate from 

 them in the lumbar vertebrae. The sacrum is long and wedge-shaped, and 

 consists of five vertebrae, all with well-developed neural spines. The ante- 

 rior sacral is articulated to the diapophysis of the last lumbar as well as to 

 the centrum, and the diapophysis of the last lumbar in like manner articu- 

 lates with the diapophysis of the penultimate. The horse and rhinoceros 

 display similar articulations. In the Tapirus terrestris the sacral articula- 

 tion is less distinct, and that between the last two lumbars is wanting. 

 The centra of the lumbars are plane in Hyrachyiis. 



The anterior ribs are, as usual, wider and flatter than the posterior, 

 and articulate with the sternum, apparently without any intervening haema- 

 pophyses. This is to be inferred from the facts that the ribs extend to the 

 sternal segments and that no traces of haemopophyses are present. The 



