FORT UNIOIST OF CRAZY MOUNTAIN FIELD, MONT. 



199 



properly compare them with the better matericals manifestly belonging 

 in a distinct genus, named Metachriacus. With the removal of the 

 extraneous material and renewed comparison of a large number of 

 specimens, it is clear that Metachriacus punitor and "Chriacus pusillus" 

 both belong in Metachriacus. The specimens previously referred to 

 "Chriacus pusillus" are smaller than those placed in Metachriacus 

 punitor, and M3 is slightly more reduced. Nevertheless, with recog- 

 nition that they are congeneric and in view of the fact that all are 

 from one horizon and locality it appears that no sharp division 

 between the small and large specimens can be made and that they 

 are merely individual variants of one species. This is borne out by 

 the statistical constants given below. 



Of Ii-Pi only the alveoli are Imown. Judged from these, there 

 were three small, subequal, closely crowded incisors, the canine was 

 moderately enlarged and procumbent (but less so than in Prothrypta- 

 codon), and Pi was a small tooth implanted vertically by a single 

 root, P2_3 are similar, but P3 is larger. Both are slender, 2-rooted, 

 pointed teeth, the outer face convex, with a sharp anterior crest and 

 the posterior and anterointernal faces excavated. There is a small 

 barely cuspidate heel and a tiny anterior basal cuspule. P4 is con- 

 siderably longer than P3 although barely higher. The anterior cuspule 

 is more distinct and the talonid much more developed, its internal 

 half basined. There is a high rudimentary metaconid, not well differ- 

 entiated from the protoconid, closely similar to that of Chriacus. 

 The lower molars are of generalized arctocyonid type except for the 

 special characters already listed. 



The symphysis is shallow, weak, and unfused, the horizontal ramus 

 long and slender, the mental foramina beneath Pi and P3. 



Upper teeth have not been found associated with lower jaws of 

 Metachriacus punitor, but there are several isolated upper teeth and 

 jaw fragments, including representatives of the three upper molars, 

 that are from the same level and locality, are harmonious in size and 

 structure, and may be referred to this species with some assurance. 

 In outline they closely resemble Chriacus but are distinguished by the 

 entire absence of a protostyle and the considerably lesser development 

 of the hypocone. 



Table 41. — Individual measurements {in mm) of Metachriacus punitor 



119212—37- 



-14 



