372 



ORDERS OF MAMMALIA. 



tlie frontals ar§ developed behind into two larger bony pro- 

 jections, most probably also of the nature of horn-cores. The 

 animal thus possessed three pairs of horns, one carried by the 

 upper jaw-bones, one by the nasals, and one by the frontal 

 bones. Whether, however, these so-called "horn -cores" 

 really supported horns, of the nature of the horns of the 

 Cavicorn Euminants, is quite a matter of conjecture ; and 

 there is much probability in the view entertained by Owen — 

 namely, that some of "them were simply covered by callous 

 integument. 



As regards the mental powers of Dinoceras, Professor Marsh 

 remarks : " The brain-cavity of Dinoceras is perhaps the most 

 remarkable feature in this remarkable genus. It proves con- 

 clusively that the brain (fig. 657, a) w^as proportionately 



Fig. 657.— A, Skull of Dinoceras, viewed from above, showing the form and size of the brain 

 B, Fore-foot of Diftocercw ; c, Hind-foot of Oinocei-as. (After Marsh.) 



smaller than in any other known Mammal, recent or fossil, 

 and even less than in some reptiles. It is, in fact, the most 



