no. 2086. SOME MAMMALS OF THE PLEISTOCENE— HAY. 519 



The bar of bone between the foramen lacerum medius and the 

 foramen lacerum anterius is thin, 3 mm., and in front has an acute 

 edge. In the other two bovines here considered the bone is con- 

 siderably thicker (from 7 mm. to 11 mm. in the bison) and the front 

 edge is obtuse. 



The parocipital process is broken off, as is also the bulla. 



The squamosal of our fossil, seen from the outside, presents some 

 features and relations of interest. In both the living bison and in 

 the jersey that part of the squamosal which enters into the temporal 

 fossa rises perpendicularly or in the jersey even slopes inward to 

 join the parietal. In the fossil bison the bone as it ascends turns 

 outward, so as to overhang very considerably. Just above the root 

 of the zygomatic process of the squamosal, at the rear of a consid- 

 erable excavation, are two considerable venous foramina. These 

 are present in the jersey skull also, and in many skulls of Bison 

 bison, but their presence, number, size, and positions are subject to 

 great variations. 



The articular surfaces for the lower jaw are placed on a higher 

 level with respect to the basisphenoid than in Bison bison. A line 

 drawn from the lowest part of one of these surfaces to that of the 

 other passes considerably above the basisphenoid. In the existing 

 bisons examined such a line passes through the body of the basis- 

 phenoid. The same statement may be made regarding the jersey 

 cow. 



In the fossil bison here described the exoccipital of the left side is 

 preserved nearly to the midline above the occipital foramen, where it 

 met the one of the opposite side. This permits the measurement of 

 the foramen. The distance from the front of the lower border of the 

 foramen to the middle of the upper border is 40 mm. ; in the jersey 

 it is 38 mm. : in the skull of the small cow buffalo this measurement is 

 40 mm., as well as in a much larger male individual. In the* fossil 

 the greatest distance across the foramen magnum, just in front of the 

 hinder borders of the condyles, was close to 50 mm.; in the jersey 

 it is 45 mm. ; in the skull of a large male bison, close to 50 mm. ; in 

 the skull of another large male bison, 45 mm.; in the cow buffalo 

 mentioned, 44 mm. It will be seen that in the fossil the opening is 

 absolutely larger than in the other animals used for comparison, 

 although they belong to specimens of evidently greater size. 



The cavity found just outside of each occipital condyle and into 

 the front of which opens the condylar foramen is much shallower 

 than in the great majority of specimens of Bison bison; but inas- 

 much as variations are observed in the latter one can not count with 

 certainty on this shallowness as a specific character. Careful measure- 

 ments indicate that the inner walls of the temporal fossae approached 

 each other more rapidly from the rear to the front in the fossil than 



