28 E. L. Troxell — Amynodonts in Marsh Collection, 



Measurements. 



M. planifrons M. rex 

 Scott & Osborn Holo- 

 1887. type 



mm. mm. 



Skull, length, incisor to condyles 550 520+ 



"Width across arches 365 360 



Face, orbit to premaxillary, ant 170 ? Ill 



Cranium, ant. of orbit to occiput 385 350 



Molar-premolar series, length 225 202 



Molar series, length 160 140 



Premolar series, length 65 61 



Diameters of teeth : 



C\ ant.-post 35 28.6 



C^, transverse 35 36 



P*, ant.-post. 25 23 



P*, transverse 45 43.4 



M^ ant.-post 47 36 



MS transverse 68 56 



MS ant.-post 60 58 



MS transverse 64 60 



Amynodon erectus, sp. nov. 



(Figs. 3-6, 76.) 



Holotype, Cat. No. 11453, Y. P. M. Upper Eocene (Uinta beds), White 

 River, Utah. 



The type of this new species is the well preserved skull 

 and jaws used by Professor Marsh in amplifying the de- 

 scription of A. advenus (1877, p. 251), figured by him in 



Y P M 

 114^3 TYPE 



Fig. 3. — Amynodon erectus, sp. nov. Holotype. Top of skull showing 

 left side crushed forward. X l/^- 



Ms work on the Dinocerata and used in the study of brain 

 capacities in extinct mammals (1884, p. 62, fig. 72). The 

 valuable internal cast of the cranium is still available for 



