THE MUSCULAR ANATOMY AND THE RESTORATION OF THE TITANOTHERES 



725 



SECTION 5. MUSCLES OF THE LIMBS AND VERTE- 

 BRAE OF OLIGOCENE TITANOTHERES 



The more robust development and marked broaden- 

 ing of many of the limb bones of the Oligocene 

 titanotheres as compared with those of the Eocene 

 titanotheres indicate corresponding changes in the 

 muscles. The principal attachments of the limb 

 muscles are indicated in Figures 652-660. 



SECTION 6. RESTORATION OF THE MUSCULATURE 

 AND BODY FORM OF BRONTOPS ROBUSTUS, AN 

 OLIGOCENE TITANOTHERE 



The restoration of Brontops rohustus is based, first, 

 upon a detailed study of the musculature of each 



pose finally adopted represents the animal in rapid 

 forward motion with the head lowered, as if for attack. 

 The position assigned to the limbs is that commonly 

 assumed under such conditions by graviportal types, 

 such as the elephant and rhinoceros. The scapula is 

 placed well above the ribs, as in ungulates generally, 

 and not so far down as it is in the mounted skeletons 

 of titanotheres in the museums. When placed in this 

 pose the fore part of the skuU is still some distance 

 above the ground. In order to lower the mouth to 

 the ground the animal possibly extended one fore 

 limb far forward and the opposite fore limb backward. 

 After the skeleton was drawn in this pose (fig. 659) 

 an outline tracing of this drawing was used as a basis 



Figure 662. — Restoration of Broniotherium gigas 



Modeled by E. 8. Christmau under the direction of W. K. Gregory. Based on the studies of the musculature and skeleton described in Chapter 

 VIII. The relative length of the skull and forearm and the depth of the thorax at the shoulder were determined from Am. Mus. 492. About 

 one thirty-second natural size. 



bony element of the skeleton, as described above, and 

 second, upon a comparative study of the general 

 appearance of the musculature of the body as a whole 

 in recent perissodactyls, as figured by several authors. 

 Some valuable hints were obtained from photographs 

 of partly dissected specimens of the white rhinoceros, 

 taken in the field by Herbert Lang, and from figures 

 of the Indian elephant by Cuvier and Laurillard. 



The first step toward insuring a lifelike pose in the 

 restoration of the living animal was to obtain a correct 

 pose for the skeleton. A cardboard manikin based 

 upon the mounted skeleton in the American Museum 

 was drawn to scale; in this manikin each movable 

 element of the skeleton was fastened to fiexible copper 

 wire, so that the pose could be readily changed. The 



for the placing of the muscles. There can be little 

 doubt as to the general position of the chief muscles 

 as seen after the removal of the panniculus and 

 platysma layer; but the precise form and size of each 

 muscle are of course more or less doubtful. In every 

 case, however, we are guided, so far as possible, by 

 the conditions observable in recent perissodactyls and 

 to some extent in the elephant. 



In the life restoration the skin is of the pachyderm 

 type, intermediate in character between those of 

 elephants and rhinoceroses but somewhat more hairy. 

 Possibly the color was more or less uniformly dark 

 gray. The feet are intermediate in character between 

 those of the rhinoceros and the elephant, as shown by 

 the skeleton. 



