32 OKEODON. 



that of Anoplotherium. Its mediiin portion bulges backward above the foramen 

 magnum, and is concave below the summit of the inion. The lateral portions of 

 the surface arc directed outwardly from the median, and are moderately concave, 

 but relatively much less than in the Camel. 



The lateral margin of the inion, or the occipital crest, is relatively less prominent 

 than in the Camel; and at its lower part is formed, as in the Deer and other rumi- 

 nants, by the elevated border of th^ pars squamosa and a process of the pars petrosa 

 intercalated between the former and the occiput. 



The occipital foramen is transversely oval and emarginate above. 



The condyles resemble those of the Ano]jlotlicrium, and do not advance upon 

 the basilar process inferiorly as in the Camel, Deer, and other ruminants. Their 

 po.sition corresponds pretty closely with that which they have in the Camel; and 

 their angle and superior and inferior faces present in the same direction. 



Inferior Vieio.—{V\. III. Fig. 1; V. 2, 3; VI. 3.) The base view of the skull, 

 in its general form, much resembles that of Anoplothei-ium ; but it is relatively 

 broader in comparison with its length, and presents numerous peculiarities. The 

 basilar process slopes on each side from a central crest, which expands at the con- 

 dyles and at its junction with the post-sphenoidal body. The surface of the latter 

 is smooth, slightly convex, and inclines slightly upward in its direction forward. 

 (III. 1; V. 2.) 



The pterygoid processes commence a little in advance, and to the outside, of the 

 position of the spheno-basilar junction, and are very oblique in their course down- 

 ward and forward. To their inner side is a shallow groove, directed to the foramen 

 lacerum, for the reception of the Eustachian tube. 



The paramastoid processes form the infero-lateral terminations of the occiput, and 

 are conspicuous objects either in the lateral or posterior view of the skull. They 

 are relatively about as long and strong as those of Anoplotherium, but are nearly 

 vertical, or bent slightly forward and outward. Their form is elongated pyramidal, 

 and the outer portion of their base abuts upon the posterior process of the pars 

 petrosa, as in the Deer; while the antei'o-internal portion rests upon the auditory 

 bulla. Antero-externally the para-mastoid process is longitudinally excavated, and 

 between its base and the pars petrosa it incloses the stylo-mastoid foramen, and in 

 advance of this the pit of reception for the styloid process. (III. 1; V. 2.) 



The mastoid process is small, as in all ruminants, and is a compressed eminence or 

 ridge forming the posterior boundary of the meatus auditorius externus. It does not 

 descend as low as the bottom of this, and projects between the auditory process 

 from which it is separated by a notch, and the base of the paramastoid process. 



The auditory process constitutes the antero-inferior boundary of the meatus, and 

 inferiorly forms a ridge-like vaginal process curving forward and inward to the 

 auditory bulla with which it is continuous. 



The latter is relatively very small to what it usually is in ruminants, and cor- 

 responds in this respect with Anoplotherium. It is convex, surmounted by the ridge 

 just indicated, rests against the paramastoid process posteriorly, and is continuous 

 with the bony process of the Eustachian tube anteriorly. Internally, as in existing 



