URSUS ARCTOS. 8l 
space in the Fen Bear contains the sockets of two small 
spurious molars, each with a simple fang (given in outline in 
Jig. 22), but there is no trace of these in the Cave Bear, save 
in very rare exceptions; and this difference cannot be the 
effect of age, because the lower jaw of the Fen Bear, which 
has the grinders moderately worn by mastication, is here 
compared with the jaw of a young and small Ursus speleus, 
in which the tubercles of the grinding teeth are all entire. 
The Fen Bear resembles the Ursus priscus in so far as the 
latter retains the first false molar, but differs in possessing 
the second, which is wanting in a younger specimen of the 
Ursus priscus ; it differs also in the greater extent of the 
interspace between the canine and the third false molar ; 
and, more importantly, in the form of that tooth, which 
in the Ursus priscus presents a second cusp on the mner 
side, and a little behind the first, which cusp is wholly 
wanting in the corresponding tooth of the Fen Bear. The 
ramus of the jaw is deeper, and the slope of the symphysis 
is more gradual. 
These characters are illustrated in the comparative views 
of the dentition of the lower jaw of Ursus Arctos, U. pris- 
cus, and U. speleus, fig. 35. 
In all the particulars in which the Fen Bear differs 
from the two extinct species above cited, from the caverns, 
it agrees with the existing Ursus Arctos, and especially 
with the darker variety of Europe, from which it does not 
appear to differ in any well-marked specific character. The 
Grisly Bear of North America agrees with the Cave Bear 
(Ursus speleus), and differs from the Ursus Arctos and the 
present British fossil representative of that species in the 
absence of the first two false molars and in the more com- 
plicated crown of the third false molar. 
G 
