214 



BULLETIN 16 9, UNITED STATES NATIONAL MUSEUM 



Diagnosis. — Differing from Didymidis in the relatively smaller and 

 much simpler P3-4 and relatively lower and longer trigonid of Mi, 

 from Viverravus in the wider and more triangular P4 and more defi- 

 nitely basined talonids, and from other known miacids in the absence 

 of M3. 



Figure 



-Ididopappus mustelinus Simpson, U.S.N.M. no. 9296, right lower jaw: a, Crown view; b, in- 

 ternal view. Three times natural size. 



Figure 61.— Ididopappus mustelinus Simpson, U.S.N.M. no. 9295, left upper jaw, in two fragments but 

 associated, crown view. Three times natural size. 



ICTIDOPAPPUS MUSTELINUS Simpson 



Figures 60, 61 



Ididopappus mustelinus Simpson, 1935d, p. 237. 



Type. — U.S.N.M. no. 9296, right lower jaw with Ps-Mi and talonid 

 M2. Collected by A. C. Silberling. 



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

 cene horizon. Crazy Mountain Field, Mont. 



Diagnosis. — Sole known species of genus. Measurements below. 



Discussion. — From the alveoU the canine was a large procumbent 

 tooth and was followed by a diastema. Pi may have been absent and 

 Pa 1-rooted, but this is not certain. P3 is a very small and simple tooth 

 consisting of a somewhat compressed main cusp followed by a shght 

 unbasined heel. P4 is shorter than Mi but nearly as liigh and is sub- 



