CONTENTS VII 



Chaptjsr VI — Continued. 



Section 5 — Continued. Page 



Subfamily Menodontinae 505 



Systematic descriptions of genera and species in the Alloys phylum 506 



The Menodus monophjdum 518 



Systematic descriptions of genera and species in the Menodus phylum 522 



Section 6. The brontotheriine group 538 



Group characters 538 



Sexual characters 540 



Subfamily Megaceropinae 540 



Systematic descriptions of genera and species in the Megacerops phjdum 541 



Subfamily Brontotheriinae 550 



Systematic descriptions of genera and species in the Broniotherium phylum 555 



Chapter VII. Evolution of the skeleton of Eocene and Oligocene titanotheres 583 



Section 1. Methods by which the titanothere skeleton has been studied 583 



Principles of the evolution of the limbs of hoofed animals 583 



Size and proportions of Eocene titanotheres 584 



Divergence and convergence in the skeleton of polyphyletic series 586 



Diverse adaptive types of limb structure ^ 586 



Terms used in describing the skeleton of the titanotheres 588 



Section 2. The postcranial skeleton of lower Eocene titanotheres 590 



Subfamily Lambdotheriinae 590 



Subfamily Eotitanopinae 59 1 



Section 3. Middle Eocene groups and phyla J : 598 



Double parallelism in the palaeosyopine and Manteoceras-DoKchorhinus groups 598 



Family and subfamily characters of skeletal parts in middle Eocene titanotheres 599 



Systematic descriptions of middle Eocene titanotheres 612 



Subfamily Palaeosyopinae 612 



Subfamily Manteoceratinae 631 



Section 4. The postcranial skeleton of upper Eocene titanotheres 636 



Subfamily Dolichorhininae 636 



Subfamilies Telmatheriinae, Brontopinae?, and Diplacodontinae 652 



Section 5. The postcranial skeleton of Oligocene titanotheres 662 



Subfamily Brontopinae 664 



Subfamily Menodontinae 678 



Subfamily Brontotheriinae 689 



Bibliography for Chapters III- VII 698 



ILLUSTRATIONS 



Plate 

 Frontispiece. Herd of Brontotherium platyceras. Page 



I. .4, Eruption of the crater of Taal, Philippine Islands; B, Flooded area 140 



II. A, Qjo Alamo, San Juan County, N. M.ex., looking north; B, Base of Puerco formation resting on eroded 



surface of Ojo Alamo sandstone 140 



III. A, Upper Torrejon beds, Torrejon Arroyo, Sandoval County, N. Mex.; B, Exposures of Puerco formation 



east of Ojo Alamo, N. Mex 140 



IV. A, Eohippus-Coryphodon zone. Little Sand Coulee, Clark Fork Basin, Wyo.; B, Phenacodus-Nothodecles- 



Coryphodon zone, Clark Fork Basin, north of Ralston, Wyo 140 



V. A, Typical "Lysite" locality, at Cottonwood Draw, north of Lost Cabin, Wyo.; B, Typical "Gray Bull" 



locality, south of Otto, Big Horn Basin, Wyo 140 



VI. A, A typical Huerfano locality, west of Gardner, Huerfano Basin, Colo.; B, A typical "Lost Cabin" locality, 



east of Lost Cabin, Wind River Basin, Wyo 140 



VII. A, Henrys Fork Table, looking northward across Henrys Fork, Bridger Basin, Wyo.; B, Grizzly Buttes, south 



of Mountain View, Uinta County, Wyo 140 



VIII. A, Northwest point of Haystack Mountain, head of Bitter Creek, Sweetwater County, Wyo.; B, View 



southeastward from Laclede station, Sweetwater County, Wyo 140 



IX. A, Columnar sandstones, LTinta A, White River Canyon, Uinta Basin, Utah; B, Panoramic view. White 



River Canyon below Wagonhound Bend, Uinta Basin, Utah 140 



X. A, Northern boundary of Coyote Basin, Uinta Basin, Utah; B, Divide between White River Canyon and 



Coyote Basin, Uinta Basin, Utah 140 



XL A, North face of Beaver Divide, Wind River Basin, Wyo.; B, Exposures at Wagonbed Spring, Beaver 



Divide, Fremont County, Wyo 140 



XII. A, Contact between Titanotherium zone and Pierre shale. Cedar Creek, Big Badlands, S. Dak.; B, Badlands 



south of White River, Utah, showing the Diplacodon zone 140 



XIII. " Mauvaises Terres" or Big Badlands of South Dakota 140 



XIV. Exposures at Quinn Draw, Big Badlands, S. Dak., showing summit of Chadron formation 140 



XV. A, South end of Sheep Mountain, near head of Corral Draw, Big Badlands, S. Dak.; B, Cedar Creek, Big 



Badlands, S. Dak., showing the Oreodon zone overlying the Titanotherium zone 140 



