1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 347 
The measurements of the teeth, as given by Cope, are as follows: 
mm. 
Lower molar (?mi) — antero-posterior diam............ 6.25 
€ “ transverse +3 ‘ CS bias. Meet G; 
. premolar (?p,) — antero-posterior “ ............ $:5 
. f transverse say Re 5. 
INCERT SEDIS. 
Opisthotomus flagrans Cope, 1875,' from the Wasatch of New Mexico, 
was described at the same time as O. astutus. The type, which is lost, is a 
lower jaw fragment with a single damaged tooth which Cope took to be 
the last molar. It is an unidentifiable type; the tooth as shown by Cope’s 
figure has a considerable resemblance to the fourth milk molar of Phenaco- 
dus primevus but not close enough for certain identification. 
Phenacodus sulcatus Cope, 1874,? from the Wasatch of New erase was 
based upon a last upper molar of the left side (Nat. Mus. Coll. No. 1027). 
The tooth has the outline of a last molar of Phenacodus but differs in showing 
no trace of mesostyle and in having a metaloph developed as well as a pro- 
toloph, a character in which it resembles the Perissodactyla. The outlines — 
of the tooth, however, together with the much reduced metacone and a 
rather indistinct hypocone, give the-tooth an appearance very much unlike 
that of Kohippus or any other Lower Eocene Perissodactyl. The structure 
of the tooth and a certain peculiar irregularity or unevenness of the enamel 
surface leads me to think that this type is a malformed tooth of Phenacodus. 
It is about the size of P. brachypternus, the smallest species. Measurements 
are: anteroposterior diameter = 6. mm., transverse diameter = 8.1 mm. 
EKohyus distans Marsh, 1894.2 The type of this species and genus is a 
last upper molar of the left side (Yale Mus. Coll. No. 11889), from the 
“Coryphodon beds of New Mexico.” As the name implies Marsh consid-_ 
ered this an Artiodactyl with Suilline affinities. In the same paper he 
described a second species, HL. robustus, from the “Lower Eocene of New 
Mexico,” a type which Sinclair has correctly referred * to Periptychus, a 
Torrejon genus. Marsh’s drawing of the type of EH. distans is somewhat 
misleading. -An examination of the specimen shows a facet for the m? 
which serves to orient the tooth, which gives it a different position in the 
jaw from that suggested by the drawing. The outline of the tooth is similar 
1 System. Cat. Vert. Eoc. N. Mex., p. 16; Ext. Vert. N. Mex., p. 152, pl. xlv, fig. 8. 
2 Rep. Vert. Foss. N. Mex., p. 11; 1877, Ext. Vert. N. Mex., p. 179, ol, xiv, fig. 7. 
3 Am. Jour. Sci., Vol. XLVIII, p. 259, fig. 1. 
4 Bull. Am. Mus. 1914, p. 267. 
