12 THE AMERICAN BISONS. 
would just about equal in length and thickness the average size of the horn- 
cores of the adult male of either the aurochs or the American bison. 
Several teeth that apparently belong to this species have been described 
by Dr. Leidy, together with some that represent a smaller species. The five 
molar teeth from Natchez, Mississippi, found in association with the remains 
of Mastodon, Equus, Ursus, Cervus, Megalonyx, and Mylodon, are the largest teeth 
belonging to any known species of Bison, being considerably larger than those 
of Bison priscus described by H. von Meyer, from Mannheim, Germany, as 
well as much larger than those from California, which are referable to the 
species next described in the present paper. The specimens from Natchez 
Dr. Leidy thus describes: “In the upper molars the external side exhibits six 
folds, relatively not more prominent than in the common ox. Internally, 
between the principal lobes, the accessory column is very well developed and 
robust. The crescentic enamel pits or islands of the grinding surface are 
more simple than in the ox, and appear relatively more capacious as a result 
of their greater simplicity or less degree of inversion of the sides of the pits 
[a difference common to all the members of the bison group, as compared 
with the representatives of the restricted genus Bos]. The last lower molar 
also presents a well-developed accessory column between the anterior pair of 
the principal lobes externally, and in the worn-down specimen, upon the trit- 
urating surface forms a correspondingly larger fold. In the unworn speci- 
men the summit of the posterior lobe bifurcates anteriorly, one portion 
joining the postero-internal fold of the middle lobe, the other the postero- 
external angle of the same lobe.” 
These are the only teeth thus far described that seem to me to be referable 
to the Bison latifrons. ‘Those described by Dr. Leidy, from California,* evi- 
dently belong to the smaller western form (Bison antiquus), of which Dr. 
Leidy has also figured and described the skull. The tooth from Pittston, 
Luzerne County, Pennsylvania,t found with remains of Mastodon americanus 
and Equus major, seems to wholly lack the accessory column, judging from the 
figure, “the oval islet” being apparently mot formed by the wearing down of 
the accessory column. In other respects the tooth also resembles the corre- 
sponding tooth of Ovibos, and it seems to me is undoubtedly referable to the 
extinct musk-ox and not to any form of Bison. It is in any case too small 
for a tooth of Bison latifrons. 
* Ext. Vert. Fauna, ete., p. 254, pl. xxviii, figs. 6, 7. 
{ Ibid., p. 255, pl. xxviii, fig. 8. 
