342 Bulletin American Musewm of Natural History. [Vol. XXXIV, 
preserved one seems to have been nearly as long in the temporal region as 
P. primevus but more slenderly built. A pair of lower jaws (No. 15764) 
shows an extreme length of approximately 160 mm. as compared with 195 
mm. in P. primevus. 
From the Clark Fork beds are several ied specimens which 
seem to fall into this group. From the Sand Coulee beds are lower jaw 
fragments, and from the Lost Cabin some ten or twelve fragmentary speci- 
mens are doubtfully referred to this species. Most of these agree in size 
and in-the reductien or’absence of metaconules. In Nos. 14794 and 14796 
this cusp 1s absent from both the first and second molars. 
Two of these Lost Cabin specimens (Nos. 14784 and 14797) appear to 
represent either a well marked variety of P. intermedius or, more likely, a 
_distinet species. The first specimen consists of jaw fragments with po-m; 
the second specimen of a first or second lower molar and a p*, with which 
are associated fragmentary limb bones, a ealeaneum and astragalus, and 
parts of both fore feet, one nearly complete. Both of these specimens 
show a much greater reduction of the premolars than is observed in any 
specimen of P. intermedius from the Gray Bull beds. In No. 14797 the p* 
has the same transverse diameter as the p* of the type, but 1s a much nar- 
rower tooth, antero-posteriorly, which coincides with the antero-posterior 
reduction of the lower premolars of No. 14784. 
There is no foot or limb material of P. intermedius oe the Gray Bull 
beds for comparison with the Lost Cabin specimen. Compared with the 
fore foot of P. primevus it shows a trifle more slender Me I but otherwise 
no differences except in size. 
Measurements. 
No. 14797 P. primevus 
|i 8 NS es Ene ee ey OE cp peu te ay a. 
VEG Vonks eC ae neh A Eso RANG Wore GR Ge et 36. 
UG ol ae ee By Per Rea ean eS 28. (est.) 
The difference in size of the feet is greater than one would expect to find 
between P. primevus and the type of P. intermedius. I hesitate to separate 
these Lost Cabin specimens, because of the lack of comparative material, 
and because the individual variations in this genus are so great. 
From the Sand Coulee beds a specimen consisting of upper and lower 
jaws (No. 16131) shows in the lower teeth the same reduction of the pre- 
molars, but not of p*. 
Krom the lower horizon of New Mexico a lower jaw (No. 16246) is in- 
termediate in size between P. intermedius and P. hemiconus. 
