PETERSON: A REVISION OF THE ENTELODONTIDA 55 
from the Titanotherium beds, these openings [supraorbital foramina] are of good 
size, are placed quite near to the median line, and have well-marked vascular 
channels running forward from them.” On the ventral border of the mandible the 
knob-like processes are well developed. In the type represented in Fig. 10, Pl. 
XXVIT (Ext. Mam. Fauna of Dakota and Nebraska) these proc- 
esses are shown to be of quite large size. In the dorsal vertebrae 
of the specimen, which Professor Scott referred to E. ingens, the 
canals perforating the walls of the neural arch for the spinal 
nerves are small and quite irregular in their position, indicating 
that they had a less important function than was the case in 
Dinohyus and Sus. The trapezium (tm. in fig. 10) is present in 
the manus of the splendidly preserved specimen in the Princeton 
Museum. 
Archeotherium coarctatum (Cope). 
Type: A left mandibular ramus with molar-premolar series 
complete. Fic. 10. Inside View 
5s z i a 2 of Carpus of A. ingens 
Horizon: Lower Oligocene, Titanotherium beds? ; : 
Leidy, showing Trape- 
Locality : Cypress Hills, District of Assiniboia, Canada. ziumin Position. } nat. 
Locality of Type: Collection of the Geological Survey of i (Princeton Mus. 
‘ - Cat., No. 10885. ) 
Canada, Ottawa. 
The name Hntelodon mortoni was used by Professor Cope in his first report of 
the presence of remains of the Hntelodontidx in Canada (17a, p. 163). Later he re- 
ferred this material to “ Elotherium” coarctatum, which again was changed by him 
in 1891 (28, p. 20) to “ Hlotherium arctatum.” The type as figured on Plate XIV 
(28) clearly indicates this species as valid and the more important characters may 
be quoted from Professor Cope’s description : “The species differs from 2. mortoni, 
with which it agrees nearly in size, in haying all the premolars in a series uninter- 
rupted by diastemata except a very short one between Pm. IIT and IV [Pz and Palas 
The second premolar [Ps] "is the most elevated, and the third and fourth [Pz and 
P;]* are abruptly smaller. The fourth [Pz] has one ™ compressed grooved root. 
- .. The posterior, or fifth tubercle is well developed, especially on the M. III 
[M3].”"* (See crown view in fig. 11.) 
Without catalog number. 
“ From the illustration it would appear that there were probably two roots on P;, perhaps coalesced near the 
crown which is usual in many species from higher horizons. 
« The notation of the teeth enclosed in brackets [ ] is given by the writer, in order to facililate the understand- 
ing of Prof. Cope’s description, in which he used the now obsolete method of numbering the teeth from the back of 
the jaw forward. 
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