178 



SKELETON OF THE HIPPOPOTAMUS. 



antlers, or are " solid-horned." The horns of the giraffe 

 are peculiar; they are short and simple, are always 

 covered by a hairy integument, and are never shed. 

 They relate in position to both the frontal and parietal 

 bones. In all other ruminants, the horns are developed 

 from the frontals exclusively, although they sometimes, 

 as in the ox, project from the back part of the cranium; 

 but the frontals; in such cases, extend to that part. The 

 horn of the rhinoceros consists wholly of fibrous horny 

 matter. 



The even-toed hoofed animals that do not ruminate 

 have no horns. The osteology of this division is here 

 illustrated in the hippopotamus (Fig. 31). The skeleton, 



Fig. 31. 



SKELETON OP THE HIPPOPOTAMUS AMPHIBICS. 



in its strength and massiveness, presents a greater con- 

 trast with that of the giraffe than the rhinoceros's skeleton 

 does with that of the horse ; there are, nevertheless, as 

 will be shown in the concluding summary, more essential 

 points of resemblance to the giraffe's skeleton than to 



