On a fossil Ox from the Mississippi. 285 



of the malar, before this last meets the orbital process to form 

 the zygomatic arch. 



A portion of the external meatus auditorius is preserved on 

 both sides. The distance between them in a strait line is G*7. 



We have already alluded to the remarkable thickness of 

 the parietes of this cranium. The following dimensions taken 

 with much care, will give a more accurate idea on this sub- 

 ject. 



The thickness of the occipital bone an inch above the 

 great foramen, - - - - - - - 1*6 



The frontal, measured between the bases of the horns, 1*9 

 Parietes of the temples, ----- «9 



At the occipital crest, - - - - -2* 



Within the cavity of the cranium, the longitudinal furrow 

 for the insertion of the falx of the dura mater was observed. 

 It was deep and strongly marked. We .also noticed within, 

 the part corresponding to the posterior clinoid sphenoidal 

 processes in man. The antero-poslerior diameter of the 

 cavity of the cranium, was 4*5. Transverse diameter 2*7. 



We might enter into more minute details, but it is con- 

 ceived that enough has been said to enable us to compare it 

 with the skulls of those recent or fossil animals, with which 

 we are acquainted. The remarkable frontal processes former- 

 ly supporting the horns would naturally, in the absence of 

 other evidence, lead us to refer our specimen to the ruminant 

 family of quadrupeds, and to the genus Bos. But none of 

 that genus are now to be found in our country, whose crania 

 in the slightest degree resembles the one under consideration. 

 The Dos americanus, or bison, has short, round, and straight 

 horns, which, of course, are very different from our fossil. 



All naturalists and travellers, who have had occasion to 

 speak of the extensive collection of fossil bones found at the 

 Big-bone Lick, speak of the bones of the ox, or bison, as 

 associated with those of the mastodon. Few of the former 



Vol. II. 36 



