1869. | OLASSIFICATION OF THE CARNIVORA. 9 
hollow between these processes and the bulla is placed the stylo- 
mastoid foramen (s), through which the facial nerve makes its exit 
from the cranium*. 
Immediately in front of the commencement of the meatal prolon- 
gation of the tympanic, at the base of the postglenoid process of the 
squamosal is a conspicuous opening called foramen glenoideum (g), 
which leads to a venous canal which runs upwards and backwards 
into the lateral sinus. 
Still more forward, immediately to the inner side of the glenoid 
fossa, is the foramen ovale of the alisphenoid (0), transmitting the 
third branch of the fifth nerve, and bounded and partly covered on 
the inner side by a strong ridge of bone. Close in front of this is 
the hinder aperture of the large canal (a), bridged over by a lamina 
of bone from the alisphenoid, to which Mr. Turner has particularly 
directed attention under the name of “alisphenoid canal.”” Through 
this the ectocarotid artery runs for a part of its course. It opens in 
front by a common aperture with the foramen rotundum (a’). 
With this the list of the parts to which it is necessary to refer at 
present concludes. The description just given will apply, with 
trifling modifications, to all known species of the genus Ursus, in- 
cluding the subgenera Thalassarctos, Helarctos, and Prochilus. 
Passing to the animals usually considered most nearly allied to 
the Bears, Procyon (fig. 3, p. 10) has the auditory bulla more dilated 
and prominent, it is true, than in Ursus, but with the same general 
form, 7. e. rising abruptly on the inner side, most prominent near the 
middle of the inner edge, sloping off behind and before this point, and 
flattened at the outer side, where it is continued into the prolonged 
under lip of the auditory meatus. Moreover it is simple within, 
undivided by any distinct septum; on looking into the meatus the 
opposite wall can be distinctly seen, or a probe can be passed to it 
without meeting with any impediment. 
The aperture of the carotid canal (car) is large, and rather more 
advanced and more distinct from the foramen lacerum posticum (/) 
than in the Bears. The paroccipital process (p) stands away from 
the bulla; the mastoid (m) is very distinct. The condyloid foramen 
(c) is freely exposed on the surface, and quite distinct from the 
foramen lacerum posticum. The glenoid foramen (g) is large and 
conspicuous, though somewhat overlapped by the margin of the 
tympanic bone. ‘The alisphenoid canal is completely wanting ; this 
is the most important distinction from the true Bears. 
In Nasua the bulla is still more rounded and prominent ; indeed 
its resemblance to that of the Bear is chiefly in its simplicity, and in 
the prolongation of the auditory meatus. The carotid foramen is 
advanced to the middle of the bulla. The paroccipital and mastoid 
processes, and condyloid foramina, are as in Procyon. The glenoid 
foramen is more conspicuous. There is no alisphenoid canal. 
Cercoleptes presents a great difference from Nasua and Procyon 
* The modifications of this foramen in situation will not be noticed hereafter, 
as they depend simply on the amount of inflation of the external portion of the 
bulla. 
