On the Recent and Extinct Irish Mammals. 59 
These discrepancies isolate the humerus of the latter from all 
the others. 
The dimension of the humerus from Loch Gur, as compared 
with the same bone in the Shandon specimen and Polar Bear, are 
as follows :— 
Humerus | Humerus |Humerus of 
PSs from Loch | from Shan- Ursus 
Gur. don Cave. | maritimus, 
PL LVafig: 9:| | Big- 8. Fig. 7. 
Inches, Inches. Inches. 
Length from epiphysial junction of head, : 15° 14°5 10°6 
Maximum diameter (antero- pastere?) at Bae 
junction of head, 2 : 25 2°3 2°6 
Maximum breadth of ditto, . . 2:5 : 2° 
Width of the distal extremity (articular surface), = 3°3 28 2-6 
‘Greatest thickness of ditto, é 14 ei 11 
Entire width of distal extremity, . : 5 5: 42 4: 
Antero-posterior diameter at deltoid insertion, . 21 16 15 
Greatest thickness of inner condyle, : - dt tI nish 
These data show relatively that the humerus of the Polar 
‘Bear is a stouter bone altogether than obtains in the two fossil 
instances. 
J submitted the femur from Loch Gur to a similar comparison 
with the same bone in the above species. Professor Owen,* in his 
exhaustive differentiations of fossil ursine remains, states in con- 
nexion with the Polar Bear, “that the lesser trochanter in U. 
maritimus, as in U. ferox, is thrown wholly to the posterior 
surface of the bone, the inner margin being continued beyond it.” 
In the Ursus fossilis, and in the Gigantic Cave Bear, U. speleeus 
the same prominence, though on the posterior surface, projects 
somewhat beyond the inner margin, owing to the bone of the 
Polar Bear being broader in proportion to its length, and the great — 
width of its extremities. This character seems persistent in the 
Polar Bear—at all events, in many femora I have examined ; 
whilst several femora of Ursus spelzeus, Ursus fossilis, U. ferox, 
and U. arctos, were indistinguishable as far as the position of the 
lesser trochanter was concerned, having all of them this tubercle 
almost on the margin, more or less, as seen at @ Plate IV., fig. 
2, of the Shandon, and fig. 3 of the Loch Gur femur, but never so 
far back as in Ursus maritimus, fig. 1 
* British Fossil Mammals, p. 97, 
