MERYCHYUS 



229 



Diligent search has failed to show any trace of this species, either described (in manuscript) or 

 based on any actual specimen. There is no reference to it in the catalogue of fossil vertebrates at 

 the American Museum. 



It must be considered, therefore, a nomen nudum, without standing, at the present time. 



Merychyus harrisonensis Peterson 1906 

 Figs. 166-168 



Original Reference: The Miocene beds of western Nebraska and eastern Wyoming and their vertebrate 

 fauns. Ann. Carnegie Mus., IV, pp. 35, 37-40, figs. 7-8. 



Type Locality: Vantassel Creek, Niobrara County, Wyoming. 



Geologic Horizon: Lower Miocene (lower Harrison). 



Type: Holotype, Cat. No. 1341 CM., fairly well-preserved skull of moderately old individual. No lower 

 jaws, and skull somewhat crushed vertically. Specific name given to indicate geologic horizon in which specimen 

 was found. 



Specific Characters: The skull is mesocephalic, with a length greater than in any other 

 species of the genus, with the possible exception of M. fariogonus. The malar is not deep below the 

 orbit, and the zygomatic arch is light. The greatest expansion, slightly back of the postorbital bar, 



Figs. 166-167. — Merychyus harrisonensis Peterson. Skull. HT. Cat. No. 13 + 1 CM. 



1906.) Above, lateral view; below, superior view. 



1/2 nat. size. (After Peterson, 



is only moderate. It was probably not far from horizontal in lateral view, with but a slight upward 

 trend above the glenoid surface. The facial vacuities are rather large, being formed mainly in the 

 lacrimals and maxillaries, apparently a little in the frontals, and absent in the nasal bones. In the 

 young animal these vacuities are relatively larger than in the adult. The nasals are not reduced, are 

 widest at the maxillaries just back of the anterior narial opening, are wedge-shaped, and are poste- 

 riorly pointed. They are convex transversely and seem to rise anteriorly. The latter feature is, I 

 believe, entirely due to crushing. The lacrimal bone is moderately large on the face and bears a small, 

 shallow fossa. The frontals are not reduced, unless by a very small amount anteriorly, where the 

 facial vacuities have encroached upon them; and this apparent encroachment may well be more 

 apparent than real, in consequence of the breaking down of that part of the frontal subsequent to 



