466 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Figure 396. — Lower jaws of the Brontops and Menodus phyla 

 A, Brontops brachycephalus, Am. Mus. 1495; B, B.dispar, Nat. Mus. 4941 (type); C, B. robustus, Prince- 

 ton Mus. 10061; D, B. robustus, Yale Mus. 12048 (type); E, Menodus torvus. Am. Mus. 6365 (type); 

 F, M. trigonoceras , Nat. Mus. 4745; Q, M. giganteus, Am. Mus. 506; H, M. giganteus. Field Mus. 

 P 5927. All one-twelfth natural size. 



Figure 397. — Lower jaws of the Diplo- 

 clonus and Allops phyla 



A, Allops walcotti (?), Nat. Mus. 4247; B, A. marshi. 

 Field Mus. P 6900; C, A. angustigenis, Ottawa Mus. 

 (cotype); D, Diplodonus bicornutus. Am. Mus. 1476 

 (type); E, D. tyleri, Amherst Mus. 327 (type). All 

 one-twelfth natural size. 



Figure 398. — Heads of Oligocene titanotheres, showing proportions, lip structure, and horns 

 Modeled by Charles R. Knight. A, Brontops (bracbycephalic); B, Menodus (dolichocephalic); C, Megacerops (hyperbrachycephalio); D, Broniotherium (brachycephalic). 



