182 BULLETI]N' 16 9, UNITED STATES KATIOXAL MUSEUM 



Width p^ 7.5 mm. 



Length m^ 9.4 mm. 



Width m> 10.0 mm. 



Length m^ 5.5 mm. 



Width xn? 9.3 mm. 



Length of lower dental series c to nis 05.0 mm. 



Length mi to ms 28. 5 mm. 



Length m2 9.4 mm. 



Width m2 7-5 mm. 



Length ms 9.9 mm. 



Width ma 6.5 mm. 



Depth of jaw at m2 21.5 m.m. 



Depth of jaw at p2 18.2 mm. 



Total basal length of skull (estimated) 155.0 mm. 



Width of skull across orbital region, including zygomas (estimated) _ _ 65.0 mm. 



"Even in our present knowledge of the claenodont group it is diffi- 

 cult to determine the limits of individual variation and species char- 

 acters ; and it is quite probable that some of those here stated have a 

 much wider significance than I have given them, while others may have 

 less importance. This statement applies equally to the following 

 more detailed description of the type specimen. 



"The skull is not greatly specialized but shows the following char- 

 acteristic modifications: glenoid fossae situated forward in position as 

 in the Miacidae; sagittal crest high and prominent (primitively cor- 

 related with the small brain, and the large canines with which were 

 doubtless associated heavy temporal muscles), occipital crest but little 

 expanded ; nasals long, slightly widening forward and overlapped by a 

 considerable portion of the maxillary in the normal creodont-carnivore 

 way; posterior root of zygoma prominent with roof of glenoid fossae 

 depressed below the level of basisphenoid plane as in the bears; rela- 

 tive position and arrangement of cranial foramina, also as in the 

 XJrsidae, that is, the optic foramen is placed well forward of the ante- 

 rior sphenoidal fissure which lies close to the foramen rotundum, with 

 the anterior opening of the alisphenoid canal just below them; the 

 ethmoid foramen lies nearly above the optic foramen and well behind 

 the postorbital process (an important character, as the position of this 

 foramen marks the posterior border of the cribriform plate of the 

 ethmoid); foramen ovale, and posterior opening of alisphenoid canal 

 connected by a groove or depression which is separated from the 

 basisphenoid plate by a prominent ridge of the alisphenoid." 



Discussion. — Dr. Gidley also well described and figured the various 

 known limb elements of this species. As already suggested, most of 

 the distinctions noted by him were based on comparison with a single 

 specimen of Claenodonferox, and they disappear or seem of very little 

 importance when more material is brought into the comparison. The 

 proportionate widths of radial facets on scaphoid and lunar are 5.3:8.1, 



