SAUROPOD GENUS CAMARASAURUS. 393 



true number. Eighteen vertebrae are consigned to the back, eight 

 too many. Fifty-seven vertebrae are consigned to the tail, not far 

 from the correct number. A complete set of claws is consigned to 

 both the fore and the hind feet. 



Still Unknown Parts of Camarasaurus. 



1. In the accompanying restorations and reconstructions of Ca- 

 marasaurus it is observed that our knowledge of this animal is still 

 very incomplete regarding the structure of the pes, the foot bones 

 being based on our knowledge of the pes of Apatosaurus or Bronto- 

 saurus. 



2. It is also unknown or uncertain whether these animals pos- 

 sessed a set of abdominal ribs. One rib has been found which may 

 possibly represent a member of the abdominal rib series. 



Fig. 2. Restoration of the external appearance of Camarasaurus. Pho- 

 tograph of a model of Camarasaurus made under the direction of Prof. W. 

 K. Gregory by Mr. E. S. Christman with the cooperation of the authors. 

 This model is the result of very careful comparison of the Camarasaurus 

 skeleton with previous sauropod models and with various living reptiles ; it 

 embodies extensive myological studies by Professor Gregory, and a thorough 

 analysis of the characters of the skeleton. 



3. The vertebral formula is still uncertain, although it is probable 

 that the number was as follows : cervicals 13 ; rib-bearing dorsals 10, 

 dorsosacral i ; consolidated primary sacrals 3 ; caudosacral i ; 

 caudals 53. 



