QUATERNARY FAUNA OF GIBRALTAR. 69 
The evidence, therefore, as to species afforded by the dentition of the Gibraltar Bear, 
is not very satisfactory, and leaves it doubtful whether it should be referred to U. fossilis 
or to a large form of U. arctos. 
Another specimen in which we may seek for further evidence is the axis vertebra, 
which seems to present some distinctive characters from that of U. ferox; but these 
are perhaps not very marked, nor probably of much intrinsic importance. And _ it 
must be remembered that the Gibraltar bone is of a young animal, and that with which 
it was compared of fully mature age. The comparative dimensions of these bones are 
given in the following table. 
Comparative Dimensions of Axis of Ursus ferox and U.——, Gibraltar. 







a : Width across | 
| Total length. ee Minas aioe posterior Length of | Diameter of | 
marae ibe serio articular spine. neural canal. 
F process, 
| —— ——— 
in, in. in. in. in. 
1. Gibraltar specimen ...... 27 2-0 2:7 2-6 1:0 
Pe Umer Oy BOs) 3 pias «= 2°8 1-9 2-4 3:3 0-9 
3. U. arctos, 218c, B.M. .... ws me aa 2:35 | an 
4, U.isabellinus .......... 5 alOry 2:3 2-65 0-6 








From these figures it will be seen that the main differences as regards dimensions 
are in the greater width across the anterior articular processes, which would indicate 
of course a longer atlas and skull, and probably, therefore, a larger animal, which is 
quite in accordance with the comparative dimensions of the teeth in the two cases. 
The neural canal also is larger in the Gibraltar bone, which is an indication in the 
same direction, whilst, on the other hand, the total length is slightly less, and that 
of the spine considerably so—both of which differences may reasonably be assigned 
to the different ages of the individuals. 
In other respects it is to be observed that in the axis of U. ferox the posterior 
articular facets are larger and rounder, the transverse processes much larger, the neural 
lamine thicker, and the odontoid process smaller—all of which differences may also 
be fairly referred to age and stature. 
The spine in U. ferox is produced backwards some way behind the level of the 
posterior articular processes, whilst in the Gibraltar bone it is on a level with them; 
and in the former it is much hollowed posteriorly: but these characters may also 
perhaps be referred to difference of age. 
I have also compared the axis with that of U. arctos (var. isabellinus'). The latter 
is of about the same general size, but differs from the former in several particulars, 
some of which, but not all, can also be regarded as due to age. 
' I may mention that in this specimen of U. isabeilinus in the British Museum there are six sacral yertebre. 
VOL. X.—PART I. No. 3.— August 1st, 1877. L 
