54 MEMOIRS OF THE CARNEGIE MUSEUM 
closely related as these genera appear to be and I would suggest a reéxamination of 
the British specimen by those who may have access to it. While Haplocanthosawrus 
and Cetiosaurus are certainly generically distinct | believe they may pertain to the 
same family. 
Although there are undoubted close similarities in structure between Haplocantho- 
saurus and the three genera of British Sauropods mentioned above, yet, if we can rely 
upon the characters represented by a single vertebra, it isin South America that 
there has been found the remains of a Sauropod dinosaur showing the closest 
relations with this genus. I refer to the dorsal vertebra recently described and 
figured by F. Baron Nopsca ° and provisionally referred by him to Bothriospondylus. 
From Nopsca’s figures, it will be seen that from the material at hand it is not 
generically distinguishable from Haplocanthosaurus the corresponding vertebra of 
which it resembles very closely. Note for instance the simple neural spine, elevated 
diapophyses, high neural arches, reduced centra, character and arrangement of the 
various lamin, position and character of the tubercular and capitular rib facets, 
all of which are characters similar to, indeed almost identical with, those found in 
the median dorsals of Haplocanthosawrus. Without claiming that the two are 
undoubtedly congeneric I wish to emphasize the very striking similarity in structure 
which they exhibit. 
From the above study of the material constituting the types of Haplocantho- 
saurus priscus and H. utterbacki the present author feels justified in regarding that 
genus as representing the least specialized member of the Sauropoda yet discovered. 
Of the families of Sauropoda already proposed its closest affinities are undoubtedly 
with the Morosawride and I prefer to include it in that family rather than to erect 
for it a new family, although some will doubtless think it deserving of the rank of 
a distinct family, the Haplocanthosawride. According to that classification of the 
Dinosauria which it appears to me is most acceptable, considering our present 
knowledge of the group, the taxonomy of Haplocanthosauwrus would be best expressed 
by considering it as a well-marked genus of the family Morosauridx of the order 
Sauropoda, subclass Dinosauria, class Reptilia. 
Probable Habits of the Sawropoda. 
Great diversity of opinion has been expressed by various authors regarding the 
habits of the different genera of Sauropod dinosaurs. Owen, on page 39 of his 
“ Fossil Reptilia of the Great Odlite,” speaks as follows of the probable habits of these 
®Sitzungsberichten der kaiserl. Akademie der Wissenschaften in Wien. Mathem. naturw. Classe, 
Bd. CXL., Abth. 1, Feb., 1902, pp. 108-114. 
