THE POSE AND LOCOMOTION OF DIPLODOCUS 21 



his view that the sauropods were derived from the carnivorous dino- 

 saurs. He sums up his conclusion as follows (p. 351): 



Die Sauropodcn ein friihes Theropoden-Stadium festhalten and fixiren 

 und so eine gleichartige und relativ wenig weiterbildungsfahige Masse 

 bilden, die sich wohl nur infolge des Riesenwuches bis zum Schluss der 

 Kreidezeit behaupten konnte. 



Regarding the time of origin of the Sauropoda Dr. v. Huene has the 

 following to say (p. 351): 



in der Zeit zwischen dem Schluss der Trias und dem Auftreten von 

 Dystroph?cus im alteren Jura ist die erste Umpragung zum Sauropoden- 

 Typus erfolgt. 



Dr. V. Huene calls attention to the numerous characters common to 

 the Theropoda and the Sauropoda, and he believes that the latter 

 inherited these common characters from the former suborder. Such 

 a derivation would, the present writer holds, require extremely impor- 

 tant modifications in the structure of the early Theropoda. The 

 hind foot had, at the end of the Trias, become decidedly mesaxonic, 

 with the hallux greatly reduced and probably somewhat turned back- 

 ward. To create the foot of Diplodocus, for example, the hallux and 

 the second digit must have been stimulated to increased growth ; that 

 is, the foot must have been made entaxonic; whereas, the upright gait 

 that is usually attributed to Diplodocus ought to have increased the 

 size of the middle digits and further reduced the hallux. The meta- 

 tarsals that had become lengthened had to be shortened. The fore 

 limb, that in the late Triassic theropods had become reduced in length, 

 sometimes greatly so, must have taken on renewed vigor and increased 

 size. All the modifications that had been attained and all the ten- 

 dencies established that looked toward making bipeds out of these 

 theropods had to be reversed. 



Probably little or no importance can be attached to the fact that no 

 remains of sauropods have yet been encountered in the Triassic 

 deposits. It is certain that but a small proportion of the animals 

 that made those Connecticut Valley tracks have left us other traces 

 of their existence. Then, it is extremely probable that comparatively 

 few of the residents of that region were accustomed to parade on those 

 desolate and dangerous tidal flats. The sauropods especially, being 

 slow-footed plant-eaters, would naturally have sought localities where 



