HATCHER: OSTEOLOGY OF HAPLOCANTHOSAURUS 57 
ming organ. In arriving at any reasonably accurate conception of the habits and 
usual mode of locomotion of these dinosaurs the structure of the limbs would seem 
to be of the very first importance although they have not as yet been given more 
than a passing consideration in this connection. The limbs and feet are now pretty 
well known in several genera of the Sauropoda and in so far as the Jurassic forms 
are concerned their structure shows them all to have been strictly quadrupedal, with 
massive and rather long limbs and feet both behind and in front, the fore limbs with 
one or two possible exceptions being the shorter. In no instance yet discovered is 
there any marked or even noticeable tendency toward abbreviating or subordinating 
the limbs along the lines so universally characteristic of the aquatic or amphibious 
recent reptilia or mammalia. The structure of the limbs and feet in all the Sauro- 
pod genera, where those elements are known, furnish to my mind conclusive evi- 
dence that they were first of all ambulatory organs whose usual and normal func- 
tions were to give support to the body and enable the animal to walk about over 
the dry earth or to wade in the shallow rivers, swamps, lakes and other waters 
while in search of food. When engaged in the latter occupation their great size 
aided by their long necks would enable them to essay waters of no inconsiderable 
depth with little inconvenience. 
Second: As to the character of the associated fossils. 
Wherever remains of Sauropod dinosaurs have been found in this country, there 
has been found associated with them in more or less abundance the remains of 
Theropod and Predentate dinosaurs. The classic quarry near Canyon City, Colorado, 
where the types of the two species of Haplocanthosawrus described above were found 
has also yielded remains of Diplodocus, Brontosawrus, Morosawrus,, Ceratosawrus, 
Allosaurus, and Stegosawrus, besides other dinosaurs, crocodiles, turtles, fishes and 
diminutive mammals all from the immediate sandstones in which the dinosaurs 
occur. While in the adjacent clays there are numerous small lenticular masses of 
limestone abounding in fresh-water gasteropods and remains of small fresh-water 
plants. And in the clays themselves at a few especially favored localities the shells 
and casts of several species of Unio occur in great abundance. ‘The character of the 
fauna and limited flora found associated with these dinosaurs, whether considered 
individually or as an assemblage is not what would be regarded as strictly aquatic. 
Such aquatic forms as are found like the bivalves, gasteropods, fishes, turtles and 
crocodiles indicate for the most part shallow waters or at least streams and lakes of © 
only moderate extent and depth. 
Third: The condition of the remains as they lay imbedded in the matrix will 
afford some evidence as to the habits of the Sauropoda, for it is evident that if these 
