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head so characteristic of this species. In fact, the general 
contour of the head of an animal prepares you for the form 
of the skull. In the Brown Bear a slight concave depression 
is observable between the orbits, and an apparent shortening of 
the nasal bones, which agrees with the semi-convex forehead 
in the skull of the fossil Arctos and Priscus. In these, also, the 
great width of the zygomatic region is perceptible : which 
character also agrees with the breadth of the head in the 
recent Brown Bear. In the Cave Bear (Ursus spelaeus), the 
forehead is abruptly protuberant, with a sudden concavity 
towards the nasal bones, the lateral region of the skull is 
much compressed, and the superior maxillary bones protrude 
considerably beyond the nasal orifice, apparently indicating 
that this gigantic bear had a very flexible and extended nose ; 
and I am not aware that skulls of this species are ever seen 
in which the great convexity of forehead is not a prominent 
character, and the other features just enumerated are not also 
constant. In the Bornean and Sloth bears, the heads are 
comparatively short and broad, and the skulls have a peculiar 
convexity, which almost approaches the segment of a sphere 
in longitudinal extent. 
The number and position of the permanent premolars 
ought also to be considered a character of sufficient im- 
portance to depend upon for specific difference. Specimens 
may occur in which their number are not equal, an instance 
of which, E. W. Scott, Esq., informs me, is in the Royal. 
Dublin Society's Museum. This skull is of Ursus Arctos, in 
which there are two premolars on one side of the upper jaw, 
and only one on the other. This, however, I do not consider as 
an exception to the rule, and venture to think that, upon 
close inspection, there will be discovered some slight 
indication of a premolar having been lost, and the space 
nearly obliterated by the natural absorption of the alveolar 
cavity ; and, if there is not such indication, it is evidently a 
