CONTENTS IX 



Plato Page 



CCXIV. Fourth left metacarpal of the type of Brontops robustus Marsh i 894 



CCXV. Fifth left metacarpal of the t3'pe of Brontops robustus Marsh 894 



CCXVI. Proximal phalanges of left manus of the type of Brontops robustus Marsh 894 



CCXVII. Phalanges and sesamoids of the type of Brontops robustus Marsh 894 



CCXVIII. Pelvis and sacrum of the tj'pe of Brontops robustus Marsh 894 



CCXIX. Pelvis and sacrum of the tj'pe of Brontops robustus Marsh 894 



CCXX. Left femur of the type of Brontops robustus Marsh 894 



CCXXI. Left tibia of the type of Brontops robustus Marsh 894 



CCXXII. Left patella and left fibula of the type of Brontops robustus Marsh 894 



CCXXIII. Left astragalus of the type of Brontops robustus Marsh 894 



CCXXIV. Left calcaneum of the type of Brontops robustus Marsh 894 



CCXXV. Left navicular and left cuboid of the type of Brontops robustus Marsh 894 



CCXXVI. Left ectocuneiform and left mesocuneiform of the type of Brontops robustus Marsh 894 



CCXXVII. Left fourth metatarsal of the type of Brontops robustus Marsh 894 



CCXXVIII. Left manus and left pes of the type of Brontops robustus Marsh 894 



CCXXIX. Restoration of the skeleton of Brontops robustus Marsh 894 



CCXXX. Left lunar and right trapezoid referred by Marsh to Brontotherium gigas 894 



CCXXXI. Pelvis and sacrum referred by Marsh to Brontotherium gigas 894 



CCXXXII. Left second metatarsal referred by Marsh to Brontotherium gigas 894 



CCXXXIII. Left third metatarsal referred by Marsh to Brontotherium gigas 894 



CCXXXI V. Left fourth metatarsal referred bj' Marsh to Brontotherium gigas 894 



CCXXXV. Phalanges of left second, third, and fourth digits referred by Marsh to Brontotherium gigas 894 



CCXXXVI. Skeletons of Megacerops acer, male and female 894 



Figure 



640. Heads of four titanotheres 703 



641. Facial musculature and nasal cartilage of Manteoceras 704 



642. Facial musculature and nasal cartilage of Menodus giganteus 705 



643. Facial musculature and nasal cartilage of Brontotherium platyceras 706 



644. Relation of the contour of the head to the skull and jaws in living perissodactyls 707 



645. Model of half of skull and head of Palaeosyops leidyi 708 



646. Models of half of skuU and head of Eotitanops borealis and Manteoceras manteoceras 709 



647. Heads of titanotheres of middle and upper Eocene time 710 



648. Heads of Eotitanops, Manteoceras, Protitanotherium, and Brontotherium, front view 711 



649. Heads of Eotitanops, Manteoceras, Protitanotherium, and Brontotherium, side view 711 



650. Occiput of Brontops robustus, showing probable location of muscles 712 



651. Probable position of muscles of dorsal vertebrae in Brontops 713 



652. Right scapula of Brontotherium, showing principal muscle attachments 714 



653. Left humerus of Brontops robustus (type) , showing probable musculature 715 



654. Left radius of Brontops robustus (type) , showing probable musculature 716 



655. Left ulna of Brontops robustus (type), showing probable musculature 716 



656. Arrangement of the muscles of the flexor surface of the manus of Mesatirhinus petersoni 717 



657. Left femur of Brontops robustus (type) , showing probable musculature 719 



658. Left fibula and left tibia of Brontops robustus (type) , showing probable musculature 720 



659. Skeleton and restoration of Brontops cf. B. robustus 722 



660. Restoration of the superficial muscles of Brontops cf. B. robustus 723 



661. Restorations of nine species of titanotheres, Eocene and Oligocene 724 



662. Restoration of Brontotherium gigas 725 



663. Angles of muscular insertion and "parallelogram of forces" 728 



664. Angles of insertion of muscles to pelvis and femur in horse and mastodon 729 



665. Graviportal adaptation in the astragalus 729 



666. Cursorial and graviportal adaptations in horse and elephant 730 



667. Cursorial adaptation in fore limb and hind limb of horse 731 



668. Angulation of the fore limb in graviportal types 732 



669. Angulation of limb bones at shoulder and hip joints in Equus, Brontops, and Mastodon 733 



670. Hind limbs of cursorial and graviportal types 734 



671. Five types of scapula, cursorial to graviportal 740 



672. Forms of distal articular surface of humerus 742 



673. Seven forms of ilia, showing cursorial and graviportal adaptations 743 



674. Adaptive forms of ilia and sacral attachment 744 



675. Limb structure of perissodactyls: Fore limbs of Heptodon and Tapirus 745 



676. Limb structure of perissodactyls: Hind limbs of Heptodon and Tapirus 747 



677. Limb structure of perissodactyls : Fore limbs of paleotheres 74s 



678. Limb structure of perissodactyls: Hind limbs of paleotheres t 749 



679. Limb structure of perissodactyls: Fore limbs in four American rhinoceros subfamilies 750 



680. Limb structure of perissodactyls : Fore limbs in four Old World rhinoceros subfamilies 751 



681. Limb structure of perissodactyls: Hind limbs of rhinoceroses found in North America 751 



682. Limb structure of perissodactyls: Hind limbs of rhinoceroses found in the Old World 752 



