ARCHAEOTHERIUM. 57 
deeper; the post-glenoid tubercle is shorter and relatively very much more robust; 
and the os tympanica, instead of being slightly swollen at the inner termination of 
the vaginal crest of the auditory process, as in the former, is developed into a bulla 
relatively as large as in the Californian Deer. 
In Lucrotaphus Jucksoni (Fig. 6), the auditory bulla forms a large, simple mam- 
millary eminence, which abuts against the sphenoid bone anteriorly and the para- 
mastoid process posteriorly, and rests with its base internally upon the margin of 
the basilar process and the conjunction of this with the sphenoidal body, and is 
outwardly continuous with a ridge the homologue of the vaginal process. 
In Eucrotaphus auritus (Fig. 5), the auditory bulla has the same connections as 
in the former, but in addition rests against the post-glenoid tubercle; and it is rela- 
tively slightly larger, and laterally compressed. 
Fam. 2.—PARIDIGITATA ORDINARIA. 
Gen. ARCHAEOTHERIUMNE, Lempy: (Zntelodon? Aymard.) 
Archaeotherium is a remarkable genus of suilline ungulata combining apparent 
ruminant and carnivorous characteristics. In the form of its superior molar teeth it 
exhibits an affinity to the extinet Choeropotamus, Cuvier, and in a less degree to 
the Hyracotherium, Owen; but, judging from a sketch in Gervais’s Zoologie et Pale- 
ontologie Frangaises,’ of the upper molars of ntelodon, Aymard, it approaches 
this much more nearly than either the former. Indeed, the posterior five 
superior molars of Entelodon and Archaeotherium are so alike in relative position, 
proportion, and form, that I consider it doubtful whether the latter is distinct from 
the former; but not having an opportunity of examining the original descriptions 
and figures of Aymard,’ nor of extending the necessary comparisons, I have pro- 
visionally retained the generic name originally proposed. 
Archacotherium Mortomi, Lrrpy. 
(Puate VIII; IX; X. Figs. 1-7.) 
Archacotherium Mortoni, Leidy: Proc. Acad. Nat. Sei., 1850, v. 92; Owen’s Rep. of a Geol. Surv. of Wise., 558. 
Archaeotherium (Entelodon?) Mortoni, Leidy: Owen’s Rep. ete., refer. to Table X. 
The species Archaeotherium Mortoni was established in the Proceedings of the 
Academy of Natural Sciences (Vol. V. p. 92, for 1850), upon a fragment of a face 
containing the third and fourth premolars of the left side, presented to the Academy 
by Mr. Alexander Culbertson. 
Later, I have been enabled very greatly to extend our knowledge of this animal 
by the investigation of several interesting specimens in the collection of Dr. Owen. 
One of these is a portion of the face very much mutilated, of an adult individual, 
te Pe LOZ ps 2526, fos 1 
* Mem. Soc. Agric. Sci., ete., du Puy, t. xii. p. 240; 1848. Gervais. 
