CONTENTS XIII 



Figure Page 



302. Skulls of titanotheres of the Manteoceras-DoKchorhinus group 359 



303. Skulls of Manteoceras manieoceras 363 



304. Type skull of Manieoceras manteoceras 366 



305. Skulls of Manteoceras manteoceras and Palaeosyops leidyi 367 



306. Skulls of Manteoceras manteoceras and M. washakiensis 367 



307. Skull of Manteoceras manteoceras, side view 368 



308. Skull of Manteoceras manteoceras, anterior half 368 



309. Incisors and canines of Manteoceras manteoceras 369 



310. Lower jaw of Manteoceras 370 



311. Skulls of Manteoceras manteoceras and M. washakiensis 371 



312. Type skull of Manteoceras uintensis •- 373 



313. Upper canines and incisors of Manteoceras uintensis 374 



314. Restoration of Protitanotherium emarginatum 374 



315. Lower jaws of Protitanotherium and Brachydiastematherium 375 



316. Type skull of Protitanotherium emarginatum; reconstruction, side view 376 



317. Type skull of Protitanotherium emarginatum, front and side views 376 



318. Nasal region in three specimens of Protitanotherium 377 



319. Sections of the nasals and horns of Protitanotherium emarginatum 377 



320. Lower jaw of Protitanotherium emarginatum 378 



321. Lower jaw of Protitanotherium superbum 381 



322. Phylogenetic relations of the species of Metarhinus, Mesatirhinus, Dolichorhinus, and Rhadinorhinus 383 



323. Top view of the skull in the Manteoceras-Dolichorhinus group 385 



324. Palatal view of the skull in the Manteoceras-Dolichorhinus group 385 



325. Leidy's cotypes of Palaeosyops Junius 386 



326. Type skull of Mesatirhinus megarhinus 389 



327. Type skull of Mesatirhinus petersoni 390 



328. Skull of Mesatirhinus petersoni, side, top, and palatal views 391 



329. Skulls of Mesatirhinus petersoni, front and occipital views 392 



330. Incisors, canines, and premaxillae of Mesatirhinus 392 



331 . Lower jaws of Mesatirhinus 394 



332. Lower jaw of Mesatirhinus sp. with deciduous dentition 395 



333. Imperfect cranium of Mesatirhinus petersoni? 396 



334. Geologic section of the Bridger formation in the Washakie Basin 397 



335. Restoration of Dolichorhinus longiceps ■ 398 



336. Skull and lower jaw of Dolichorhinus hyognathus 398 



337. Skulls of Dolichorhinus hyognathus and modern horse 399 



338. Geologic section of the Eobasileus-Dolichorhinus and Metarhinus zones in the Uinta Basin 400 



339. Skulls showing progressive dolichoceplialy in the Mesatirhinus-Dolichorhinus phylum, side view 401 



340. Skulls showing progressive dolichocephaly in the Mesatirhinus-Dolichorhinus phylum, top and palatal views 402 



341. Upper premolars of Mesatirhinus, Dolichorhinus, and Metarhinus 403 



342. Skull of Dolichorhinus intermedins 406 



343. Skulls of Dolichorhinus intermedins, D. heterodon, and D. longiceps 408 



344. Skull referred to Dolichorhinus longiceps? 409 



345. Hyoid apparatus of Dolichorhinus longiceps? compared with that of a modern tapir 410 



346. Skulls of Dolichorhinus 411 



347. Skull of Dolichorhinus hyognathus, palatal view 412 



348. Skulls of Dolichorhinus hyognathus, front and occipital views 413 



349. Skull of Dolichorhinus hyognathus, side view 413 



350. Upper incisors and canines of Dolichorhinus hyognathus : 414 



351. Lower incisors and canines of Dolichorhinus hyognathus 414 



352. Left upper canine of Dolichorhinus hyognathus 414 



353. Lower jaws of Dolichorhinus 415 



354. Skull of Sphenocoelus uintensis 418 



355. Type skull of Eometarhinus huerfanensis 419 



356. Skull of Metarhinus fluviatilis 423 



357. Right lower premolars of Metarhinus fluviatilis 424 



358. Lower jaws of Metarhinus 425 



359. liOwer jaw o{ Metarhinus? (Rhadinorhinus?) sp 426 



360. Skull and deciduous teeth of type of lieterotitanops parvus 426 



361. Type skull of Metarhinus earlei ; 427 



362. Type skull of Rhadinorhinus diploconus, side and top views 432 



363. Type skull of Rhadinorhinus diploconus, top and palatal views 433 



364. Type skull of Rhadinorhinus diploconus, side, front, and occipital views 434 



365. Skulls of Eotitanotherium osborni , 436 



366. Nasals and horn swellings of Eotitanotherium osborni 437 



367. Two upper raolara of Eotitanotherium (" Diploceras") osborni 438 



368. Type skull of Diplacodon elatus, partial reconstruction, palatal view 439 



369. Type skull of Diplacodon elatus, upper jaw and zygoma 440 



