688 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 41. 



WV<?I 



SKELETON OF CAMPTOSAURUS BROWNI. 



Although Prof. O. C. Marsh made the first pictorial^ restoration of 

 Camptosaurus dispar as early as 1894 the United States National 

 Museum has the distinction of being the first to erect in a Hfe-like 

 posture the actual skeleton of one of the large species of Camptosaurus, 

 and while Marsh's earlier restoration gave a good general idea of the 

 appearance of the animal, it is now known, as has been pointed out 

 previously, to have been in error in several particulars. 



The most striking of the changes brought about by the study and 

 reconstruction of these specimens is the shortening of the presacral 

 region. In the first restoration (Marsh's) there are 30 presacral ver- 

 tebrae, 9 of which belong to the cervical region, thus leaving 21 



thoracic vertebrae. The two skele- 

 '■"' tons considered here agree in hav- 



ing 1 6 dorsals each, and accepting 

 tliis as the correct number, the 

 series has been shortened by 5 

 vertebrae, making the proportions 

 quite different from the first con- 

 ception. It lessens perceptibly 

 the space between the fore and 

 liind limbs, producing a more com- 

 pact and better balanced animal. 

 It is also shown by these speci- 

 mens that all of the vertebrae pre- 

 ceding the sacrum carried ribs, 

 and therefore there are no true 

 lumbar vertebrae. 



Other features which can best 

 be appreciated in the mounted 

 skeleton are the small head, curved neck, short and widely expanded 

 body cavity, long tail, and the great disparity in size between the 

 fore and hind limbs. 



The great strength of the hind legs is at once evident from the size 

 of the femora, tibiae, and feet. (See fig. 4.) The enormous devel- 

 opment of the fourth trochanter on the femur indicates a powerful 

 caudo-femoral muscle. That the animal usually walked with an 

 upright, bipedal gait, as amplified by the small skeleton, seems appa- 

 rent, although certain characters of the fore feet appear to indicate a 

 considerable use in locomotion. 



The compact ossified carpus, with smooth, well-defined, articulat- 

 ing surfaces, short and stout metacarpals, all are indicative of a foot 



Fig. 1.— Right fore foot, Camptosaurus dispar 

 Marsh, Cat. No. 4277, U.S.N.M.; \ nat. size. 

 Seen from the front. c«, carpal two; c*, 

 carpal 4; c^, carpal five; in, intermedium; 

 mc I, metacarpal I; r, radlale; w, ulnare; I 



TO V, DIGITS ONE TO FIVE. UNGUAL OF FIRST 

 DIGIT RESTORED. 



1 Amer. Joum. Sci., vol. 47, Mar., 1894, pi. 6. 



