802 The Condylarthra. [ August, 
abundant species of the Puerco fauna, and must have had an im- 
portant place in its economy. 
IG. 10.—FPeriptychus coarctatus Cope, mandibular teeth, nat. size. Fig. 4, 
two prem dla “deep first true molar, external view; 4, do., from above; c, do., inner 
side; d, canine tooth. From Puerco beds, New Hee Original, from Re port U. 
S. Geol. Survey a, F. V. Hayden in charge 
With the genus Hemithlzus we enter a series of forms with 
simpler molar teeth and of smaller size. The intermediate tuber- 
cles of the superior molars are wanting in this genus and in Ani- 
sonchus and Haploconus, and the inferior premolars are abso- 
Haploconus OOF 
11.—Jaws of Periptychide, nat. size, except fig. ad’, Fig. a, Hi side, 
fig Sha maxillary pic. from below. Fi ig. é, right mandibular eres of 
ica aaa ; BI, do. from above. Fig. c, Hemithleus kowai rere ; 
right maxillary bone fo below. Fig. d, Ze todon sponge baer Origin o ate 
lar ramus from si ig. d’, do., — nat size, from 
port U, S. Geol. etn Terrs., "Vo Lt 
lutely simple in all three. es is 
rior true molars a diminutive of Periptychus. 
ee foe SE mire IE ER. 
otherwise in its SUP 
The internal cusp 
