1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 447 
group are of wholly different form from those of Uintanius, robust, tur- 
gid, blunt-pointed instead of blade-like and crested. Anaptomor phus 
(= Euryacodon) is difficult to place among these groups; its affinities are 
probably nearest to the fourth group, but if better known it might represent 
a fifth distinct phylum. 
In Yarsvus the jaw is of moderate length, the lower molars are most 
like those of Omomys but without inner cusp on p, and paraconids less 
median, the canine is somewhat larger and there is but one very small 
incisor not procumbent. It is not a derivative of any one of these Eocene 
genera. 
Nor do any of the Eocene genera show any especial evidence of affinity 
to Necrolemur. In this genus the paraconid is absent on mg-3, the premolars 
are most like those of the Omomyine, the interpretation of the three teeth 
in front of pe is disputed. Apparently it cannot be descended from any of 
the American Eocene genera. The quadritubercular upper molars readily 
distinguish it from all of them, and the skull characters indicate that it is 
not nearly related to Tarsius. 
In default of skulls or skeletons the reference of these genera to the 
Tarsiide is of course provisional. The four groups above distinguished 
may represent distinct families or subfamilies but the evidence is insufh- 
cient to define them properly. Wortman’s division into Omomyine and 
Anaptomorphine does not appear to be warranted; the first is doubtless 
a natural group but its rank is questionable; the second is an artificial! 
assemblage, as Dr. Wortman himself recognized, and if the Omomyinee 
are retained the remaining genera should be split up into three or four 
corresponding groups, Necrolemur being removed from the family. But 
pending a better knowledge of the various genera it is inadvisable to arrange 
them under subfamilies. | 
Key to Genera of Tarsude. 
(Lower jaw characters.) 
I. Paraconids distinct, internal metaconids opposite protoconids. No metastylids. 
M; unreduced. One small incisor, canine of moderate size. Front teeth 
subvertical. Three small premolars with triangular bases, no deuteroconid. 
Jaws Of morerate (Cepia AWERTION ooo i ee oo Pal Eh ee ecole Ses Tarsius. 
Il. Paraconids distinct, median; metaconids opposite protoconids, no metastylids, 
mz unreduced. Two incisors, i; of moderate size, ig minute. Canine of moder- 
ate size. Jaw slender, front teeth semi-procumbent. Three small premolars, 
ps with triangular base and distinct deuteroconid. 
1. Parnconids strong; enamel smooth .. ssi ck peti eke fas Bas Omomys. 
2. Paraconids reduced, enamel wrinkled...................55 Hemiacodon. 
