FOSSIL VERTEBRATES — REPTILIA 625 
The habits of these animals are a matter of great doubt. That 
they were very pugnacious, is well shown by the frequent frac- 
tures in the long and slender spines, which must have suffered 
severely when the animal got into a fight. They were car- 
nivorous in diet. 
From the Permian rocks of Russia come some very imper- 
fectly known forms that seem to belong to this group, These 
are the fragmentary remains of animals discovered for the most 
part in working the copper mines on the west flank of the Ural 
Mountains in the provinces of Kasan and Orenburg in the old 
government of Perm. The remains are almost entirely from 
the upper layers of the Permian. They did not have the 
greatly elongated dorsal spines of the American and Bohemian 
forms. 
Brithopus.— This form was described by Kutorga as early as 
1838 from the province of Kasan, from what he then called the 
Keupfersandstein, now known to be upper Permian. The speci- 
men consists of an imperfect humerus, showing the characters of 
the Pelycosauria and the African forms. 
Rhophalodon is from the same region in Russia. It is charac- 
terized by the same features of the limb bones as the former 
genus, but the skull is unusually short and of great vertical 
extent; so great, indeed, as to give to it an absurdly square out- 
line from the side view. The teeth are much stronger and 
stouter than those of the American forms, and have a tendency 
to develop in the lateral direction, giving them a rather broad 
outline and an appearance very similar to that of the American 
Pareiasauria, the Diadectide. 
Deuterosaurus, from the province of Orenburg, in the same 
part of Russia, is even more similar to the American forms than 
the Rhophalodon; the skull is almost identical in appearance with 
that of the genus Dimetrodon. It seems strange at first sight 
to find these closely related forms from such widely separated 
regions as the United States, Bohemia, and Russia; but if we 
reflect for a moment that despite the great specialization of the 
American forms in the dorsal spines, this group is the most 
