1898.] Osborn, Additional Characters of Camarasaurus. 



221 



body, wJiilc in the water, could be raised or lowered with the 

 great acetabulum acting as a fulcrum, thus presenting an analogy 

 to the Hadrosaurs, which exerted a similar movement upon land. 

 The long neck, similar in structure and almost as flexible as that 

 of an Emeu {Droniceus), could thus pass through a prodigious arc 

 in the search for food either under or above water. The neck 

 motion apparently involved the anterior non-spine-bearing dorsals 



D3 



Fig I. DrotncEtis. Cervicals 13 and 14 ; dorsals i and 2, showing absence of median spines. 

 Dorsal 3, showing large blunt median spine, resembling that of the Ca^narasaurus dorsal, 

 Fig. II of this BiiUetin, Am. Mus. Coll., No. 607. 



as in Dronnei/s, behind which the comparatively inflexible large 

 spine-bearing dorsals rose to maximum height in the sacrum for 

 the insertion of the ligamentum nuchae and elevator muscles. 



The importance of such an hypothesis of function will appear 

 in the following description and discussion, and it applies to all 

 the Cetiosauria, namely, to i\\e.Morosaurus and Diplodocus types as 

 well, which so far as known are iiniforni with the Camarasaur type 

 in the peculiar bird-like structure oj the posterior cervicals and 

 anterior dorsals and in the possession of a very powerful swim- 

 ming tail. 



Ten of the caudals in our specimen afford an interesting illus- 

 tration of the cause of the distribution of these large skeletons 



