III. EXTINCT SPECIES OF AMERICAN OX. 13 



the above name. It is well preserved, compact, heavy, and brown in color from 

 the infiltration of oxide of iron (Plate III., Figs. 1, 2; Plate IV., Fig. 1). Mr. 

 Kite discovered the specimen in the hut of an Indian, in which it was used as a 

 seat, and he was informed it was found in a neighboring gravelly bluff, near Fort 

 Gibson, on the Arkansas River. 



Compared to the cranium proper of the American Buffalo, it is relatively higher 

 and narrower. The inion is also relatively higher and narrower (Plate III., 

 Fig. 2). 



The bases of the horn-cores, instead of being placed on a line with the orbits pos- 

 teriorly, as in the Bison and Domestic Ox, are elevated above them, as in the Musk 

 Ox. They are also united together on the top of the head, forming a very remark- 

 able process, covering the os frontis like a huge exostosis (Plate III., Fig. 1). This 

 process extends from within ten lines of the inion the entire length of the os frontis, 

 or four inches anterior to the bases of the horn-cores, and two inches posterior to 

 them. Its length is ten and a half inches, and between the horn-cores it is five 

 and a half inches wide, and anterior to them five inches. At its posterior extre- 

 mity (Fig. 2), it is one and three-quarter inches thick, and at its anterior border 

 about half an inch. The whole process is remarkably rough and tuberculated. and 

 presents, in some degree, the appearance of an exostosis, the result of disease. Its 

 upper surface is depressed into a concavity, deepest between the horn-cores and 

 divided at bottom by a prominent median ridge. Laterally, the frontal process is 

 continuous with an elevated rough ridge curving in a sigmoid manner beneath the 

 base of the horn-cores. About the middle of its course this ridge comes in contact 

 with the post-orbital ridge proceeding backwards from the post-orbital arch. 



The horn-cores project outwards, downwards, and forwards. They are demi- 

 conoidal; being flattened on their antero-superior surface the whole length, but 

 in a most marked degree at the basal and distal third. The latter portion of 

 the horn-core has a slight twist directing the flat surface more upwards. The 

 under or convex surface of the horn-cores is marked by deep vascular grooves, and 

 others corresponding to ridges of the inner parietes of the horns. The flat surface 

 is relatively smooth except near the tip, where it is also marked, though in a less 

 degree, by grooves corresponding to ridges of the horns. 



The inion (Plate III., Fig. 2) is seven and a quarter inches- in height from the 

 upper margin of the occipital foramen to the top of the frontal process, or four 

 inches five lines to the parieto-occipital crest. The middle of the latter is consti- 

 tuted by a quadrilateral rough protuberance for the attachment of the ligamentum 

 nuchas. On each side below the crest is a deep oval muscular impression. 



The supra-orbitar margin is situated three inches below the line of the highest 

 part of the horn-cores, which commence above the position of the posterior fifth of 

 the orbital entrance. It is notched at its junction with the lachrymal bone. The 

 latter, one and three-quarter inches antero-internal to the notch just mentioned, 

 forms a deep lenticular depression, or larmier, such as exists in the Deer and Sheep 

 (Plate IV., Fig. 1). 



The occipital condyles in the specimen appear to have suffered in some degree 



