NO, 8 UPPER EOCENE ARTIODACTYLA — GAZIN 63 



Uinta C to justify his belief that D. uintensis from the middle part 

 of Uinta C would turn out to be a distinct and more-advanced species. 

 So far only a time interval represented by about 250 feet of Uinta 

 sediments separates them, and until more useful evidence is forthcom- 

 ing, I do not think D. uintensis should be recognized. 



The skull belonging to the portion of a skeleton that Peterson 

 named Diplobunops ultimus came from about 400 feet above the 

 base of Uinta C and hence about 150 feet above the type of D. 

 uintensis. The skull of D. ultimus is rather crushed transversely, and 

 proportions relative to those of the type of D. uintensis are difficult 

 to determine. As Peterson noted, the molars appear to be a little nar- 

 rower transversely. The primary cusp of P* has a prominent antero- 

 lingual ridge, but this seems characteristic of Diplobunops and is cer- 

 tainly present in the D. uintensis type, D. crassus, and the Badwater 

 Diplobunops specimens. Peterson noted the smaller size of the canines 

 in D. ultimus and suggested that this, together with the smaller size 

 of the skull, may be no more than a sexual character. Such differences 

 as noted do not appear to be due to any transition or development in 

 time, leading, for example, to D. crassus, so I am inclined to regard 

 D. ultimus, as well as D. uintensis, as a synonym of D. matthewi. 

 The nomen nudum, Diplobunops leotensis Peterson (1931b, p. 74), 

 evidently refers to the type of Diplobunops ultimus, as the latter was 

 found in the "Leota Ranch" area. 



MEASUREMENTS IN MILLIMETERS OF DENTITIONS IN SPECIMENS OF 



Diplobunops matthewi 



Length of upper cheek tooth series, C (at 

 alveolus )-M*, inclusive 



Length of upper cheek tooth series, P*- 

 M^ inclusive 



Upper premolar series, P^-P*, inclusive.. 



Upper molar series, M^-M^ inclusive 



C, anteroposterior diameter (at alveo- 

 lus) : greatest transverse diameter. . . 



P', anteroposterior diameter : greatest 

 transverse diameter 



P^ anteroposterior diameter : transverse 

 diameter* 



31 Overall measurements on teeth of D. matthewi type taken at or interpreted 

 from alveoli. 



32 Type of D. uintensis. 



33 Type of D. ultimus. 



