724 



MANUAL OF ZOOLOGY. 



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 Superiorly each maxillary bone carried a well-developed pro- 

 cess, probably of the nature of a horn-core. The nasals sup- 



Fig. 413. Skull of Dinoceras mirabile, after Marsh. From the Eocene Tertiary. 



port two similar but smaller horn-cores ; and the frontals are 

 developed behind into two larger bony projections most prob- 

 ably also of the nature of horn-cores. The animal thus pos- 

 sessed three pairs of horns, one carried by the upper jaw- 

 bones, one by the nasals, and one by the frontal bones ; though 

 it is possible that some of these cores were simply covered by 

 a callous integument. The nasal bones are long, and there is 

 no evidence of any proboscis. The limbs are short, the fore- 

 legs shorter than the hind-legs ; and the femur was not pro- 

 vided with a third trochanter. The tail is short and slender, 

 and the ribs are furnished with rudimentary uncinate processes. 

 As regards the mental powers of Dinoceras, Prof. Marsh re- 

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

 remarkable feature in this remarkable genus. It proves con- 

 clusively that the brain was proportionately smaller than in any 

 other known Mammal, recent or fossil, and even less than in 

 some reptiles. It is, in fact, the most reptilian brain in any 

 known Mammal. In D. mirabile, the entire brain was actu- 



