1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 101 
criticism, and considers that he has “stilled my doubts” as to the propriety 
of his reference of the specimen under consideration. But he gives no 
morphologic reasons at all for referring the bone to the Oxyzenidee or Mesony- 
chidee rather than to the Hyzenodontide. In default of such evidence the 
argument stands untouched. It is more probable that the bone represents 
an unknown or indeterminate genus of a family that: (1) does occur in the 
Oligocene; (2) does occur in the Fayiim fauna, and is the only Carnivore 
family known from that fauna; and (3) is recorded as occasionally uniting 
the scapholunar, than that it belongs to an undescribed genus of families 
that: (1) do not occur in the Oligocene but become extinct in the Eocene, 
so far as known; (2) are quite unknown to the Fayfim fauna; and (3) 
never unite the scaphoid lunar or centrale in any of the genera. 
It is quite evident from the figure that this scapholunar is not Hyenodon. 
I am well acquainted with the osteology of this genus, and while I have 
never seen among many skeletons studied, any instance of a united scapho- 
lunar, yet the form of the individual bones of the carpus would result in 
case of union of scaphoid lunar and centrale in a bone with distal facets 
of widely different type from those of the Fayfiim specimen, which differs 
from the corresponding bones of Pachyena in substantially all the same 
points that separate it from Hyaenodon. 
It is not so clear that the bone is not Pterodon or Apterodon. Its failure 
to agree in size with the limb bones assigned by Schlosser and Andrews to 
various species of these genera would be conclusive as to those particular 
species if there were any certainty that these limb bones were correctly 
referred in all cases. But there is practically no association of jaw and 
limb parts among these Faytim carnivora and the references have been made 
upon agreement in general characters, proportionate numbers, and relative 
size. Such arbitrary references are more often wrong than right; as a result 
of the study of associated specimens of single individuals we have learned 
in this museum that they are wholly untrustworthy. But even if all these 
bones were correctly referred, disagreement with them would not prevent 
the scapholunar from belonging to some other species or genus of Hyzno- 
donts. Its relative size it must be remembered is no criterion. I showed 
in 1909 among the Miacide a variation in size of teeth relative to limbs 
of 300% between different genera. 
It is and was quite obvious to me that Dr. Schlosser’s real reasons for 
assigning this bone to “ Paleonictis or Pachyena,” are the fact that these 
two genera occur in the early Eocene of Europe, and his theory that a large 
part of the Fayfim fauna is derived by immigration from the Nordea =e 
theory in which I very readily concur. If these genera of the Lower Eocene 
of Europe left descendants in the Lower Oligocene of Africa it would doubt- 
