BISON PRISCUS. A493 
orbits, being equal to its breadth; in the Aurochs, mea- 
sured at the same place, the breadth greatly exceeds the 
height, in the proportion of three to two: the horns 
are attached in the Ox to the extremity of the highest 
salient line of the head, that which separates the forehead 
from the occiput ; in the Aurochs this line is two inches 
behind the root of the horns: the plane of the occiput 
forms an acute angle with the forehead in the Ox; the 
angle is obtuse in the Aurochs: finally, that plane of the 
occiput is quadrangular in the Ox, but semicircular in 
the Aurochs.”* The ribs never exceed in number thir- 
teen pairs in any species of Los proper; the Huropean 
Bison or Aurochs has fourteen, and the American Bison 
fifteen pairs of ribs. 
The fossil cranium with horn-cores, described and figured 
by Klein in the thirty-seventh volume of the ‘ Philo- 
sophical Transactions,’ No. eceexxvi. figs. 1, 2, and 3, and 
which is now in the British Museum, well illustrates the 
characters which distinguish the Aurochs: the specimen 
was dug up near the city of Dantzig. 
Faujas,f Cuvier,{ and H. v. Meyer,$ have added abund- 
ant illustrations of the remains of the same species from 
the superficial deposits of various parts of Europe, some 
of which carry the antiquity of the Aurochs as far back 
as the period of the extinct Pachyderms of the newer 
pliocene deposits. The remains of the ancient European 
Bisons attest their larger size, and longer and somewhat 
less bent horns than are manifested by the individuals 
of the present race, but no satisfactory specific distine- 
tion has been detected in the fossils compared with the 
bones of the Lithuanian Aurochs. 
* Menagerie du Museum d’Histoire Nat. Art. Zebu. 
+ ‘Essai de Géologie,’ tom. i. pl. xvii. ¢ Loe. cit. 
¢ ‘ Uber Fossile Reste von Ochsen,’ 4to., 1832, tab. viiii—xi. 
