1864.] DR. J. E. GRAY ON THE URSID&. 679 
Section Il. DeNpRopopa. Toes short, arched; claws retractile. 
A. Tail prehensile ; soles bald. Cercoleptina. 
8. CERCOLEPTES. 
B. Tail bushy ; soles hairy. Ailurin. 
9. AILURUS. 
Section I. Bracuypopa. 
The broad-footed Bears. The feet broad and short, generally bald 
and callous below ; toes straight ; the claws exserted, more or 
less curved, blunt. 
Brachypoda, Gray, Proc. Zool. Soc. 1864, p. 506. 
Tribe 1. Ursina. 
Tail short or none; body massive ; limbs short. 
Ursina, Gray, Cat. Mamm. B. M. 72. 
They sometimes climb trees, but usually descend backwards. 
When running, they carry their young on their back. 
In the ‘ Annals of Philosophy’ for 1825, I divided the Bears into 
groups, according to the characters of their feet and claws, and into 
the genera Ursus, Danis, Prochilus, and Thalassarctos. 
The examination of the series of skulls of Bears in the Museum, 
like the examination of the series of bones of the Viverride, has 
strongly impressed me with the uncertainty that must always attend 
the determination of fossil bones, or indeed of bones of all animals 
when we have only the skulls or other bones of the body to compare 
with one another. There can be no doubt that the study and com- 
parison of the bones of the different species is very important—that 
the skull and teeth afford some of the best characters for the dis- 
tinction of the genera and species ; but few zoologists and palzeonto- 
logists have made sufficient allowance for the variations that the 
bones of the same species assume. In the Bears I have observed 
that there is often more difference between the skulls of Bears 
of the same species from the same locality than between the skulls 
of two undoubted species from very different habitats and with very 
different habits. Thus I have the skulls of some Bears, the habitat 
of which is not certainly known, which I have doubts whether they 
should be referred to the Thibet Bear (U. torquatus) or to the North 
American species (U. americanus) ; but I have referred them to the 
latter with doubt, as they were said to come from the latter country. 
It is the same with regard to the skull of a Bear that lived in the 
Zoological Gardens for years, which has the general form of the skull 
and the wide palate of the European Bear, but the long last grinder 
and some other characters of the Ursus ferox. 
This similarity of the skull is more remarkable, as no two Bears 
