OKEODON. 53 



The species is respectfully dedicated to the Messrs. Culbertson, through whose 

 aid the first specimens were obtained upon which the genus was established. 



Oreodon gracilis, Leidy. 



(Pl. V, Figs. 3, 4; VI. Figs. 1-7.) 

 Oreodon gracilis, Leidy: Proc. Acad. Nat. Sci., 1850, v., 239 ; Owen's Rep. of aGeol. Surv. of Wise, etc., 550. 

 Merycoidodon gracilis, Leidy : Owen's Rep., 550. 



This species was first characterized in a verbal communication to the Academy 

 of Natural Sciences in August, 1851, from several fragments of an upper and a 

 lower jaw containing the true molars and one premolar. 



The head is about two-thirds the size of that of Oreodon Gulhertsonii. 



The specimens, which I have had the opportunity of examining, are as follows : — 



1. Lower and upper jaws, occiput, and os frontis of an old individual. The 

 rami of the lower jaw are broken away, but on the left side it contains all the true 

 molars, the third premolar, and the fangs of those in advance. The right side of 

 the upper jaw contains the true molars, the fourth premolar, and the roots of those 

 anterior. (Plate VI. Fig. 4, the lower jaw; Fig. 5.) 



From the collection of Captain Van Vliet. 



MEASUREMENTS. 



Inches. Lines. 



Length of series of upper molars ........ 2 2 



Length of series of lower molars ........ 2 2 



Length of series of upper true molars . . . . . . .1 2 J 



Length of series of lower true molars ....... 1 4 



Distance between ends of frontal angular processes ..... 4f 



Distance between supra-orbitar foramina ....... 5 J 



2. The skull of an adult, with the end of the nose, base of the cranium, and 

 zygomata broken away. It contains upon the right side the true molai^s and the 

 fourth premolar, and on the left, fragments of all the molars. Accompanying it is 

 a portion of the lower jaw, containing the true molars. (Plate VI. Figs. 1-3.) 



From the collection of Drs. Owen and Evans. 



MEASUREMENTS. 



Inches. Lines. 



Breadth of cranium above roots of zygomata ...... 1 6 



Breadth of cranium at most prominent part of the temporal fossae . . 1 4 



Distance from bifurcation of sagittal crest to ossa nasi . • • ■ 1 6i 



Distance between supra-orbitar foramina ....... . "^ 



Length of series of upper true molars ....... 1 3 



Length of series of lower true molars ....... 1 "* 



3. A facial fragment containing on the left side the last two molars, the fangs of 

 all those in advance, and that of the canine. It is particularly valuable from the 

 left orbit being preserved entire. 



