No. 521] 



SAUROPOD DINOSAURS 



279 



both in the hind foot and fore foot. This is less marked 

 in the hind foot than in the fore foot. Such an arrange- 

 ment of the metacarpals and metatarsals is significant, 

 as has been pointed out by 

 Hatcher and Osborn and is 

 clearly shown by Abel. 

 Sternfeld brushes Abel's 

 criticism to one side, sta- 

 ting that it can be easily 

 got rid of because the 

 same arrangement exists in 

 the feet of animals which are 

 plantigrade. I would recom- ran gement ' at D pro"imai S enr nS i, 

 mend Dr. Richard Sternfeld metacarpals; 2, of metatarsals of 

 to more carefully study the >P 



anatomy of plantigrades. The structure of the feet of the 

 sauropod dinosaurs differs immensely from that of the 

 feet of all recent plantigrades and all the recent reptilia. 

 We have evidence of a rather conclusive character as 

 to the fact that the sauropod dinosaurs were decidedly 

 digiti grade in the one existing specimen of a sauropod 

 footprint, which is happily preserved, a figure of which 

 I throw upon the screen (Fig. 20). You will see as you 

 examine it that the animal must have been provided, as 

 Professor Hatcher long ago pointed out, with a very 

 large foot -pad, and that its track is not at all like the 

 track of any of the recent lacertilia. The evidence of 

 this footprint is impressive and ought to go a long way 

 toward confirming the view, which I believe is the only 

 view which we can maintain, that tlnv-r animals were more 

 or less digitigrade in the pose of their feet. 



The form of the limbs, long, straight and pillar-like, 

 in this respect differing vastly from the limbs of the 

 creeping lacertilia and crocodilia, suggests that they 

 were intended to support a weight thrown upon them 

 from above. The femur of the crocodile, as you know, 

 is bent, and the femora of many of the recent lacertilians 

 likewise show a distinct curvature of the axis. The 

 same thing is true of the fore limbs, notably in Varanus. 



