266 Annals of the Carnegie Museum. 



Measurements. 



mm. 



Length of skull from premaxillaries to occipital condyles 512 



Length of skull from nasals to occiput 477 



Length of free nasals 80 



Height of skull at orbits not including teeth 140 



Height of skull at occiput 175 



Length of upper series of cheek teeth 194 



Proportion of height of skull at occiput to length = 175 : 512 = 34 : 100. 



Another skull (No. 1586, Carnegie Museum Catalogue of Verte- 

 brate Fossils) was found at White Butte, by Harry Roberts, a rancher's 

 boy, while hunting specimens with me. It was enclosed in a block 

 of rather soft gray sandstone on the sloping surface of the nodular 

 Oreodon beds, but it had fallen down from a cliff above, the rocks of 

 which undoubtedly belong to the Upper White River beds. It prob- 

 ably came from a slightly higher level than No. 1585 just described. 

 The nasals are moderately long and taper gradually forward to the 

 tips. They are bent somewhat downward. The orbits are large and 

 the zygomatic arch slender, at least as far back as the molars extend. 

 There is quite a wide space between the tympanic and the basisphenoid. 

 The paroccipital processes are broad, flat, and rounded, and not pointed 

 at the lower extremities. Their broadest surfaces face antero-exter- 

 nally and postero-internally. To them the post-tympanics are firmly 

 united. The latter are quite thick and are roughened on the outside. 

 They are triangular in cross-section and have short blunt processes 

 extending downward and toward the post-glenoid processes from 

 which they are separated by narrow spaces, so that the external audi- 

 tory openings are not closed below. 



Measurements. 



mm. 



Length of skull from tips of nasals to crest of occiput 514 



Length of molar-premolar series I94 



Height of skull at orbits 155 



Height of skull at occiput 167 



Width of top of skull just posterior to orbits 180 



Width of skull just anterior to glenoid articular surfaces 257 



Proportion of height of skull to length 167 mm.: 514 mm. = 32.5 : 100. 



