58 Scientific Proceedings, Royal Dublin Society. 
fragments of ribs; a large right humerus, with the loss of its 
head and portion of the supinator ridge close to the insertion of the 
latter. An entire left femur and right fibula: all probably 
belonging to the same individual. The remains are deposited in 
the Museum of Science and Art. 
T have carefully compared the above humerus, femur, and fibula 
with the similar bones of the Ursus spelzeus, U. fossilis, U. ferox, 
U. arctos, and U. maritimus, as follows. The dimensions of the 
humerus, as compared with that of the bear of Shandon Cave, 
indicates a much larger individual, indeed it equals the arm bone 
of the generality of the larger cavern bears of England and the 
Continent, and shows the owner to have been a very large and 
powerful animal. 
1, The humerus of the Polar Bear, Plate IV. fig. 7, difters from 
that from Loch Gur, fig. 9,and the aforementioned, fig. 8,in being 
stouter in proportion to the length. It is broader at the 
proximal and distal ends These are well seen, and constantly 
defined in upwards of six humeri of the Polar Bear examined 
by me. 
2. The supinator ridge forms an angle in the Polar Bear; but 
it gradually curves in the other species. Unfortunately the point 
of juncture of this ridge with the shaft has been recently broken 
in the Loch Gur arm bone, and is represented by a gap in fig. 9. 
3. The internal condyle is much thicker and stronger where it 
bounds the olecranom cavity and extends to a greater distance 
from the articular surface in Ursus maritimus than in the Loch 
Gur specimen, and the other humeri which are similar to the 
latter. 
4. The deltoid ridge runs further down the shaft in the Polar 
Bear than in any of the above species. See 5, figs. 7, 8, and 9, 
5. The antero-posterior diameter of the proximal third of 
the shaft of the Polar Bear is relatively much greater thanin the 
Loch Gur and other specimens of the living and extinct species. 
There are other points in which the Loch Gur humerus differs 
from that of the Polar Bear—to wit, in the proximal third of the 
shaft being more rounded in the latter; whilst the plateau formed 
by the posterior aspect of the supinator ridge is more or less hol- 
lowed out in all, excepting the Polar Bear, 
