A skull of the White or Polar Bear (Ursus maritimus, Pallas). 

 Hunter thus records his comparisons of the fossil with the recent Bear, 

 the skull of which he has placed with them. 



" The bones sent by His Highness the Margrave of Anspach agree 

 with those described and delineated by Esper as belonging to the White 

 Bear ; how far they are of the same species among themselves I cannot 

 say. The heads differ in shape from each other ; they are upon the 

 whole much longer for their breadth than in any carnivorous animal I 

 know of; they also differ from the present White Bear, which, as far as 

 I have seen, has a common proportional breadth. It is supposed, indeed, 

 that the heads of the present White Bear differ from one another ; but 

 the truth of this assertion I have not seen heads enough of that animal 

 to determine. 



" The heads not only vary in shape but also in size ; for some of them, 

 when compared with the recent White Bear, would seem to have be- 

 longed to an animal twice its size, while some of the bones correspond 

 with those of the White Bear, and others are even smaller. 



" There are two ossa humeri rather of a less size than those of the 

 recent White Bear ; a first vertebra, rather smaller ; the teeth also vary 

 considerably in size, yet they are all those of the same tribe, so that the 

 variety among themselves is not less than between them and the recent. 



' c In the formation of the head, age makes a considerable difference ; 

 the skull of a young dog is much more rounded than an old one ; the 

 ridge leading back to the occiput, terminating in the two lateral ones, 

 hardly exists in a young dog ; and among the present bones there is the 

 back part of such a head, yet is larger than the head of the largest Mastiff; 

 how far the young White Bear may vary from the old, similar to the 

 young dog, I do not know, but it is very probable, loc. cit. p. 419." 



The skulls of the young and old White Bears in the Osteological Col- 

 lection confirm Hunter's conjecture respecting the difference of form 

 which is due to age in this species. It will be seen that Hunter adduces 

 this conjectured change as one which must be taken into consideration 

 in comparing recent and fossil crania of animals belonging to the same 

 genus : but he does not assert that the differences which he had detected 



