FORT UXIOX OF CEAZY MOUNTAIN FIELD, MONT. 181 



jerox, and there are Torre] on specimens practically identical vAih. that 

 from Montana in size and structure. The specimen probably does 

 represent C. Jerox, but the single tooth is inadequate for certain deter- 

 mination. The same statement applies to no. 9651, an isolated left P*, 

 from Loc. 53. 



There are several Princeton specimens of Claenodon from their 

 cluster of localities in Fort Union No. 3 near the center of the field. 

 These all appear to represent one species, with considerable variation 

 but not beyond that usual for this group. Morphologically they are 

 within the limits of the C. jerox group and cannot be separated from 

 that species. 



CLAENODON MONTANENSIS (Gidley) 



Figures 37-39 

 Neodaenodon monianensts Gidlky, 1919, p. 547. 



TyjM. — U.S.N.M. no. 8362, much of the skull and jaws with most of 

 the dentition, parts of fore and hind lunbs, and other fragments. 

 Collected by A. C. Silberling. 



Horizon and locality. — Gidley Quarry, Fort Union, Middle Paleo- 

 cene horizon, Sweetgrass County, Mont. 



Diagnosis. — Gidlc}^ (1919, p. 550): "About one-fifth smaller than 

 Claenodon Jerox and C. corrugatus, slightly larger than C. protogoni- 

 oides (Cope); face relatively short, rostrum deep; brain-case very 

 small and elongate; postorbital constriction long and slender; posterior 

 root of zygoma depressed below the basioccipital plane (probably a 

 primitive character and of much more than species significance), 

 giving a decidedly arched contour to the main portion of the skull 

 viewed from the side; anterior border of orbit directly above anterior 

 boundary of m^; infraorbital foramen directly above middle of p^; 

 the large, moderately recurved, slightly compressed canines with 

 root-portion much swollen and in contour difficultly distinguishable 

 from the crown into which it merges without any deviation in outline; 

 1st premolar, upper and lower, single-rooted, relatively large (com- 

 pared with p-) and closely appressed to the canine; p^ and p* trian- 

 gular, three-rooted, p* with incipient protocone; upper m^ ^^ suboval 

 in outline, much reduced with low external cusps, the metacone 

 relatively small and inwardly placed; pa and p4 with small, narrow, 

 single-cusped heels; lower jaw relativel}^ thin and deep with the lower 

 border of its anterior half but slightly curved. 



"Measurements 



Length of uppei* dental series, C to M^ (estimated) 63.1 mm. 



Length p^ to m^ 37.6 mm. 



Length p< (estimated) 7.3 mm. 



w The original has "m^", an obvious misprint. — O. Q. S. 



