70 MR. G. BUSK ON THE ANCIENT OR 
1. The spine, which is of the same length, is 1”-3 instead of 1-0, and much more 
rounded at both ends on the upper edge, and much deeper in front (exactly the reverse 
of U. speleus). Bunt viewed from above it is thinner and much more constricted 
above the posterior articulating processes. It is also deeply hollowed behind (as in 
U. feroz). 
2. The body is much narrower in the middle. 
3. The anterior articular processes are smaller and more rounded or convex. 
4, The odontoid process is smaller. 
5. But the most remarkable difference is in the size of the neural canal, which in 
UV. isabellinus is little more than half the greatest diameter of that in the Gibraltar 
bone. 
6. The form of the posterior surface of the centrum is quite different; but as the 
epiphysis is wanting in the Gibraltar specimen, the difference may perhaps be thus in 
some measure accounted for. The other, as I have observed, can hardly be assigned to 
age, nor, as it would seem, to the circumstance that the Isabelline Bear was of smaller 
size than the Gibraltar one. 
Hence, again, then, we are brought to the conclusion that the Gibraltar Bear ap- 
proached more nearly to U. fossilis or U. ferox than to U. arctos (var. isabellinus). 
As regards the metacarpals, I need only remark that, having carefully compared 
them with those of U. ferox, of which a good specimen has lately been acquired by 
the Royal College of Surgeons, I can perceive scarcely any difference worthy of note 
between them. So far as dimensions are concerned, this will be obvious from the 
accompanying Table (see Appendix, opposite). 
It will be seen, from this Table, that the Gibraltar metacarpals must have belonged 
to four individuals, and that the largest of these most nearly coincides with the speci- 
men of U. ferox in the College Museum, which, it is to be remarked, is of small size for 
that species, and, to judge from the wear of the teeth, rather old. 
In the fifth metacarpal of U. ferox the crescentic tuberosity on the outer side of the 
head is more pronounced, whilst in the Gibraltar bone it is wider just above the lower 
capitulum. But the muscular impression, or tuberosity, on the outer side below is 
more pronounced in U. ferov. The perimetral index is slightly greater in the 
Gibraltar bone; and its shaft very slightly more compressed. 
In the second metacarpal, of which there are two specimens in the Gibraltar col- 
lection, one considerably smaller than the other, though quite mature, rather more 
difference is perceptible. In the first place, the proximal end is more produced be- 
hind than in U. ferox, and the shaft in the smaller specimen very much more com- 
pressed ; but in the larger of the two this compression is not observable. The distal 
articular head in both is smaller, and less rounded than in U. ferow. 
‘ For insertion of the peroneus brevis? 
