THE JURASSIC PERIOD. 251 
suited for walking. In particular, the femur, by its head pro- 
jecting freely from the acetabulum, seems to claim a movement 
of free stepping more parallel to the line of the body, and 
more approaching to the vertical than the sprawling gait of 
the crocodile. ‘The large claws concur in this indication of 
terrestrial habits. But, on the other hand, these characters 
are not contrary to the belief that the animal may have been 
amphibious ; and the great vertical height of the anterior part 
of the tail seems to support this explanation, but it does not 
go further. . . . We have therefore a marsh-loving or 
river-side animal, dwelling amidst filicine, cycadaceous, and 
coniferous shrubs and trees full of insects and small mamma- 
lia. What was its usual diet? If ex ungue leonem, surely ex 
dente clbum. We have indeed but one tooth, and that small 
and incomplete. It resembles more the tooth of Iguanodon 
than that of any other reptile; for this reason it seems pro- 
bable that the animal was nourished by similar vegetable food 
which abounded in the vicinity, and was not obliged to con- 
tend with Megalosaurus for a scanty supply of more stimu- 
lating diet.” 
All the groups of Jurassic Reptiles which we have hitherto 
been considering are wholly unrepresented at the present day, 
and do not even pass upwards into the Tertiary period. It 
may be mentioned, however, that the Oolitic deposits have 
also yielded the remains of Reptiles belonging to three of the 
existing orders of the class—namely, the Lizards (Lacerti/ia), 
the Turtles (Cheonia), and the Crocodiles (Crocodilia). The 
Lizards occur both in the marine strata of the Middle Oolites 
and also in the fresh-water beds of the Purbeck series ; and 
they are of such a nature that their affinities with the typical 
Lacertilians of the present day cannot be disputed. The 
Chelonians, up to this point only known by the doubtful evi- 
dence of footprints in the Permian and Triassic sandstones, are 
here represented by unquestionable remains, indicating the ex- 
istence of marine Turtles (the Che/one planiceps of the Portland 
Stone). No remains of Serpents (Op/idians) have as yet been 
detected in the Jurassic; but strata of this age have yielded 
the remains of numerous Crocodilians, which probably inhab- 
ited the sea. The most important member of this group is 
Teleosaurus, which attained a length of over thirty feet, and 
is in some respects allied to the living Gavials of India. 
The great class of the Birds, as we have seen, 1s represented 
in rocks earlier than the Oolites simply by the not absolutely 
certain evidence of the three-toed footprints of the Connecti- 
cut Trias. In the Lithographic Slate of Solenhofen (Middle 
