56 EUCROTAPHUS. 
EUCROTAPHUS, Lervy. 
Eucrotaphus Jacksoni, Lewy. 
(Puate VII. Figs. 4-6.) 
Eucrotaphus Jacksoni, Leidy: Proc. Acad. Nat. Sci., 1850, v. 92. 
Eucrotaphus auritus, Lerpy. 
(Plate VII. Figs. 1-3.) 
Eucrotaphus auritus, Leidys Owen’s Rep. of a Geol. Sury. of Wisce., ete., 563. 
The genus LEucrotaphus was originally proposed in the Proceedings of the 
Academy of Natural Sciences of Philadelphia, upon a cranial fragment presented to 
the Society by Mr. Alexander Culbertson through his father, Mr. Joseph Culbertson. 
The specimen is remarkable for the great relative size of the pars squamosa of 
the temporal bone; being hardly equalled in this respect by that of the Camel or of 
Oreodon. 
The family to which Eucrotaphus belongs has not yet been ascertained with cer- 
tainty, though from the form and proportions of the cranium being so very much 
like those of Oveodon, I suspect it to have appertained to the ruminantia. 
Coincidentally, Dr. Owen’s collection contains the portion of a cfanium corre- 
sponding to that just indicated; but it belongs toa different and rather larger 
species. 
Besides the foregoing, no specimens have been discovered, which can be ascer- 
tained to belong to Hucrotaphus. From the similarity in construction of the 
cranium proper of the latter and of Oreodon, and from the decided ruminant cha- 
racters of the specimens upon which Agriochoerus has been proposed, with the 
relations of size which these bear to those of Hucrotaphus, I suspect the latter two 
are in reality the same genus. 
To the smaller species of Hucrotaphus, the head of which was about the size of that 
of Oreodon Culbertsonii, the name Eucrotaphus Jacksoni-was given in honor of my 
much esteemed and distinguished friend Dr. Samuel Jackson, Professor of the In- 
stitutes of Medicine in the University of Pennsylvania. 
For the second species the name Lucrotaphus auritus is proposed, from the rela- 
tively larger size of the auditory bulle. 
It is unnecessary to describe in detail the specimens upon which the two species 
are founded, for they agree so closely with the corresponding portion of the 
skull of Oreodon, that it is sufficient to point out the peculiarities of structure 
which distinguish them from the latter and from each other. 
The lateral and upper views of the cranium proper of Hucrotaphus (Pl. VIL. 
Figs. 1, 2, 4, 5,) are identical with those of Oreodon, except, perhaps, the pars 
squamosa is a trifling degree larger in the former, and the parietalia are rather 
more depressed in advance and upon the course of the squamous suture. 
The outline of the base view (Figs. 3, 6), and the position of the foramina are 
also the same as in Oreodon; but in Eucrotaphus, the glenoid articulation is rather 
a a ee ets 
