OSTEOLOGY OF CARNIVOROUS DINOSAURS. 



75 



by smooth but vertically concave ends. With the exception of the joint between 

 the first and second phalanx of digit III, all of the other joints in the pes are keeled. 

 Those of the median or third digit are broad and illy defined, but the remaining artic- 

 ulations have a pronounced median keel on the proximal ends and a corresponding 

 median vertical depression on the distal 

 ends, thus forming strong joints that 

 would be difficult of lateral dislocation. 



Deep lateral pits are present on both 

 sides in all of the phalanges. The ter- 

 minal plialanges are moderately curved 

 bones, sharply pointed in front, deeply 

 grooved on the side for the external 

 claw, which in life would have con- 

 siderably increased the size of these 

 appendages. The unguals of digits II 

 and III are about subequal in size, while 

 those of digits I and IV are considerably 

 reduced. 



The ungual phalanges of the pes are 

 readily distinguished from those of the 

 manus, by the greater curvature of the 

 latter, and the inferior development of 

 the bone below the articulating surface 

 for the preceding phalanx, also those of 

 the manus are more compressed trans- 

 versely. The shape of these clawed 

 unguals, appear to indicate that these 

 feet were better adapted for locomotion . , t ^r 



. '■ Fig. 52.— Left hind foot of Antrodemvs v.vlens Leidt. No. 



than lor grasping purposes. 4734, u.s.n.m. restored, j n.it. size, (after m.^rsh.) 



Measurements of left hind feet of Antrodemus valens Leidy.' 

 DIGITS. 



PHALANGIALS. 



■ First digit measurements are from the right foot. 



2 Estimated. 



