THE PKOBOSCID^E, OR ELEPHANTS. 



241 



but less striking as regards the formation of their 

 skull, may, with somewhat greater certainty, be 

 classed as a branch of the Ehinoceros tribe (see 

 above, p. 199). Both groups, however, strike us 

 nevertheless as somewhat strange, chiefly because 

 their brain can be compared only with that of 

 certain fossil reptiles, considering the size of the 



FIG. 44.- 



-Skull of Dinoceras mirabile. 

 After Marsh. 



One-nineteenth. 



skull and the thickness and mass of the spinal 

 marrow. It would seem to be a lower form even 

 than that of the Marsupials and the Monotrema. 



Two other small groups are allied to the Hoofed 

 Animals, but in regard to one of these, the genus 

 Hyrax (rock conies), no more can be said to-day 



