NO. 2021. EXTINCT BISONS OF NORTH AMERICA— HAY. 197 



In 1846 W. M. Carpenter ^ described and illustrated with two wood- 

 cuts a fossil bison which had been found at San Fehpe, on the Brazos 

 River, Texas. The skull was preserved forward to the frontonasal 

 suture (pi. 19, fig. 3). The horn-cores had lost their extremities, but 

 there remained 2 feet of the right one, and 18 inches of the left. The 

 vadth of the skull between the horns was 14 inches (357 mm.). The 

 circumference of the horn-core at the base was 17 mches (434 mm.); 

 at a distance of 18 inches from the base (probably in a straight line), 

 14^ inches (376 mm.). The width at the rear of the orbits was 14f 

 inches (376 mm.); at the front of the orbits, 11^ inches (293 mm.). 

 A comparison of these measurements with the corresponding ones of 

 B. regius shows that the width between the horn-cores was almost 

 the same; the width at the rear of the orbits 16 mm. greater in the 

 Texas skull; at the front of the orbits 28 mm. greater in the Texas 

 skull. This appears to show that the skuU of the Kansas specimen 

 narrowed more rapidly forward than that of the Texas bison. This 

 might indicate that the Kansas specimen is the male, and the Texas 

 specimen the female of the same species. Favorable to this view is 

 the fact that the horn-cores of the Texas specimen are slenderer than 

 those of the other skull. The bases of the horn-cores of the former 

 are described as being nearly round. Calculations show that the 

 diameter at the base was about 133 mm.; at a distance of 460 mm. 

 from the base it was yet 117 mm. With the specimen described by 

 Carpenter was a second upper molar; but it was so excessively worn 

 that it affords no important characters. Its length near the roots 

 was yet 40 mm.; the width, 30 mm. 



It seems to be fitting, in closing this paper, that the principal char- 

 acters by means of which the various species of North American 

 bisons may be distinguished should be presented in a more succinct 

 form than has been done on the preceding pages ; and to this end the 

 following table has been prepared: 



Synopsis of the characters of North American bisons. 



a}. Species with the bases of the horn-cores directed at riglit angles with the 

 longitudinal axis of the face. 

 bK Horn-cores, measured along the upper curve, equal to about three- 

 fourths the distance between the bases of the cores, and about equal 



to the circumference of the base antiquus. 



a?. Species with the bases of the horn-cores directed obliquely to the longitu- 

 dinal axis of the face and nearly toward the orbit of the opposite side. 

 6-. Horn-cores short, stout, and curving outward, upward, and backward; 

 length along the upper curve much less than the distance between the 



bases and not equaling the circumference of the base bison. 



h^. Horn-cores directed outward, upward, and somewhat backward; the 

 length along the upper curve usually exceeding somewhat the dis- 

 tance between the bases and about equal to the circumference of the 

 base occidentalis. 



1 Amer. Journ. Sci., vol. 1, p. 245, figs. 1, 2. 



