496 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



A, BTontops dispar, Nat. Mus. 4941 

 (type) ; depth of horizontal ramus 

 greatly diminished by vertical 

 crushing, but the symphyseal re- 

 gion was probably shallow. A 

 short diastema between pi (which 

 has dropped out) and the canine, 

 which is stout and conical. In- 

 cisors subspherical, external cin- 

 gula not so sharply defined as in 

 Menodus. 



B, B. Tobustus, Princeton Mus. 

 10061; symphyseal region crushed 

 laterally, ramus with long, 

 straight lower border, angle pro- 

 duced. Two well-developed in- 

 cisors, canine stout, diastema in 

 front of pi (which has dropped 

 out), external cingula not sharply 

 defined. 



C, B. Tobustus, Yale Mus. 12048 

 (type); ramus long and shallow, 

 symphyseal region very shallow, 

 angle very large and produced 

 downward, coronoid high, verti- 

 cal truncate. Incisors stout, ca- 

 nines very stout and short, 

 diastema in front of pi, external 

 cingula reduced, crowns of pre- 

 molars and molars less hyp.^odont 

 than in Menodus. 



All one-fifth natural size. 



Figure 423. — Lower jaws of Broniops dispar and B. robustus 



