SKELETON OF ARTIODACTYLA. 47 1 



shows two perforations. The external pterygoid process is 

 formed by the alisphenoid, the internal one by the true ptery- 

 goid ; both are far behind the bony palate, which is divided 

 from the last molar alveolus by a notch. The cranial wall in 

 the Camel is unusually thick, with a close cancellous diploe, 

 save where the air-cells penetrate the frontal and presphenoid. 

 There is no bony tentorium. The lateral sinus bifurcates above 

 the petrosal into two w4de venous canals. The hinder one again 

 di\ddes, one branch terminating on the superoccipital surface, 

 above the mastoid, the other descending to terminate at the 

 ordinary ' foramen jugular e : ' the anterior canal descends to the 

 base of the zygoma, where it also divides, one division opening 

 on the inner and the other on the outer side of the post-glenoid 

 process. In the Llama the venous opening above the rpot of the 

 zygoma is large : and there is a smaller one at the fore part of 

 the root. The foramen rotundum is blended with the foramen 

 lacerum anterius. The rhinencephalic fossa is narrow but deep. 

 The osseous septum is coextensive with the nasal bones in old 

 Camels. The angle of the mandible, id, is singularly elevated, 

 and the contour of the ascending ramus makes a convex sweep 

 to the lower border of the horizontal one. The outlet of the 

 dental canal, r, is below the laniariform premolar, s. The fore 

 part of the symphysis expands horizontally for the incisor 

 alveoli. 



In the true Ruminants the skull is characterised by the small 

 size and edentulous condition of the premaxillaries, the slender 

 zygomatic arches, the entire 

 bony rim of the orbit, the large ^^^ 



facial plate of the lacrymal, and 

 by the processes of the frontal 

 bone for the formation of horns 

 or antlers. These latter, how- 

 ever, are wanting in both sexes ^^ 

 of the Musk-deer {Moschus, 

 Tragulus),?i^\n the Camel tribe. 

 The occipital condyles, fig. 319, 



•, 1 'ill Skull, Moschus vioschiferus. 



closely approximate below : 



the paroccipital is longer than the mastoid. The temporal fosste, 

 in the formation of which the parietals, 9, take a large share, with 

 the squamosals, 10, are divided above by a parietal crest, and 

 resemble those of the Camel. There is a small vacuity between 

 the frontal, 8, lacrymal, 3, maxillary, 2, and nasal, 7, in Moschus 

 moschiferus, which does not exist in Tragulus. The malar, 4, is 



