THE SKELETON IN MAMMALIA. THE SKULL. 469 



has a curiously specialised skull ; the nasals are absent or 

 have coalesced with the frontals and the anterior nares are 

 enormously large. In all Ruminants the lachrymal is large 

 and forms a considerable part of the side of the face ; it often 

 bears a considerable depression, the suborbital or lachrymal 

 fossa, well seen in most of the smaller antelopes. The post- 

 orbital bar is complete, and the orbit is prominent and nearly 

 circular. The palatines and pterygoids are moderately large, 

 and the pterygoids have a back wardly-projec ting hamular pro- 

 cess. The squamosal is small, but has a postglenoid process. 

 The tympanic is not fused to the periotic and has a small bulla 

 not filled with cancellous bone. There is a large paroccipital 

 process to the exoccipital and the mandible has a long slender 

 coronoid process. 



In the Cervidae and Giraffidae the face is not bent down 

 on the basicranial axis as it is in the Bovidae. The frontals are 

 drawn out, not into permanent horn cores as in the Bovidae, 

 but into short outgrowths, the pedicels, upon which in the 

 Cervidae long antlers are annually developed. These antlers are 

 outgrowths of bone, and are covered during development by 

 vascular integument, which dries up and peels off when growth 

 is complete. Every year they are detached, by a process of 

 absorption at the base, and shed. They may occur in both sexes, 

 as in the Reindeer, but as a rule they are found only in the 

 male. They are generally more or less branched, and are some 

 times of enormous size and weight, as in the extinct Cervus mega- 

 ceros. In young animals they are always simple, but become 

 annually more and more complicated as the animal grows older. 



In the Giraffe the frontals bear a small pair of bony cores, 

 which are at first distinct, but subsequently become fused to 

 the skull. In the allied Sivatherium, a very large form from 

 the Indian Pliocene, the skull bears two pairs of bony out- 

 growths, a pair of short conical outgrowths above the orbits, 

 and a pair of large expanded outgrowths on the occiput. 



The opening of the lachrymal canal is commonly double 



