OSTEOLOGY OF HAPLOCANTHOSAURUS,' WITH DESCRIPTION OF A 
NEW SPHCIES, AND REMARKS ON THE PROBABLE HABITS 
OF THE SAUROPODA AND THE AGE AND ORIGIN 
OF THE ATLANTOSAURUS BEDS. 
By J. B. Harcuer. 
The present paper is the third of a series of memoirs based on the fossil verte- 
brata in the collections of the Carnegie Museum. ‘These memoirs, prepared either 
directly by the curator of the Department of Vertebrate Paleontology, by his assis 
tants, or others under his general direction, will continue to appear at irregular 
intervals. ‘Their chief purpose will be to describe in detail and to illustrate with 
fidelity some of the more important fossil skeletons in the collections. While in 
every instance these papers will be based on material belonging to the collections of 
the Carnegie Museum, for the sake of completeness, wherever other and supplemen- 
tary material is accessible in the collections of other museums it will be utilized and 
the fullest credit will, in all such instances, be given for such favors. The preca- 
rious conditions attending the preservation, fossilization, and final recovery of the 
skeletons of extinct vertebrates have necessarily been such as to render the occur- 
rence of really complete skeletons conspicuously rare. This is especially true of the 
gigantic Sauropoda, and notwithstanding the very large collections in several of our 
leading museums, it is still possible to determine anything like the complete oste- 
ology of the different genera only by selecting the best preserved skeleton of each as 
a basis and supplementing this from material pertaining to the same genus but to 
other skeletons and belonging to the same or other museums. Owing to the cordial 
relations at present existing between the various museums of this country, aided by 
‘Proce. Biol. Soc. Wash., Vol. XVI., 1903, pp. 1 and 2, and p. 100. 
