1915.] Matthew and Granger, Lower Eocene Wasatch and Wind River Faunas. 217 
b. M* and heel of ms small, entoconid of m; imperfectly separate from hypo- 
conulid 
me CEN eRe RMN Seay cath cas Gime yo a ee Son Ge el vit FH. miticulus 
c. M*and heel of m; large, entoconid of m; distinct from hypoconulid 
rs rideale aes GEMS ess Mei RAR CAG OM On WM og NE ited biitone is UN Yea na -H. wortmana 
Aa Mite IO aS a ead eae oe ae H. mentalis 
c. Hypocone strong on m!-3, p* subquadrate 
d. Mand heel of m; large, elongate, entoconid of m; distinct 
Sx. igus - 8 mateo simpler Ce es oc eke a H. powellianus 
6.~ Mis =-20 mm. pe more complex: 5 el H. walcottianus 
D. Hypocone strong on m!~, variable on m?’, pt subquadrate 
é. Mand heel of m; large, entoconid of m3; distinct 
Premolars more crowded, ps quadrangular, roots of p, connate or eodapletcly 
united. All from Middle Eocene. 
fo) DRG a eo a Ee eG ie on eager ies eae aS H. paulus 
So Ee ae Te SRA CO PG Gh een gine ee mown ea ae H. minusculus 
Fae 1 SRE i's | 2 Ug Mr re GONE, Ae ce ora Gane ee H. lepidus 
RQ > lh ares Be aa Se os cus aaa set H. despiciens 
Lt.) Mig = hb tam.) deuterocoie 0 9 4s So ok SE OR ak H. marshi 
ps oRroaus simplex Loomis 1905. 
Hebei semplex Louse 1905. Amer. Jour. Sci., 1905, Vol.“ XX, /p. 419, 
fig. 2, type only. 
Type, a lower jaw fragment in the Amherst Museum. 
This species is characteristic of the red-banded basal zone (Sand Coulée 
beds) of the Wasatch, although the type is from the later Gray Bull horizon 
and does not display the primitive characters so clearly as the older speci- 
mens. | 
M? and the heel of m3 are much reduced, hypocone weak on m'’, absent 
Be 
‘pi? < 
2 ON ie K S 
Fig. 3. Hyopsedus simplex Loomis, No, 16842, upper and lower jaw fragments. Sand 
Coulée beds, Clark Fork basin, Wyoming, Upper molars, lower molars and ps, crown and 
external views, three times natural size. , : 
