ICHTHYOSAURUS. 
169 
find not only animals allied to Crocodiles, and 
nearly approac;hing to the Gavial of the Ganges; 
but also still more numerous gigantic Lizards, 
that inhabited the then existing seas and es- 
tuaries. 
Some of the most remarkable of these reptiles 
have been arranged under the genus Ichthyo- 
saurus, (or Fish Lizard), in consequence of the 
partial resemblance of their vertebrae to those 
of fishes. (See Plate 1, Fig. 51, and Plates 
7, 8, 9.) If we examine these creatures with 
a view to their capabilities of locomotion, and 
the means of offence and defence, which 
their extraordinary structure afforded to them ; 
We shall find combinations of form and me- 
chanical contrivances, which are now dispersed 
through various classes and orders of existing 
animals, hut are no longer united in the same 
genus. Thus, in the same individual, the snout 
of a Porpoise is combined with the teeth of a 
Crocodile, the head of a Lizard with the vertebrae 
of a Fish, and the sternum of an Ornithorhy nchus 
with the paddles of a Whale. The general out- 
line of an Ichthyosaurus must have most nearly 
resembled the modern Porpoise, and Grampus. 
It had four broad feet, or paddles, (PI. 7), and 
terminated behind in a long and powerful tail. 
Some of the largest of these reptiles must have 
exceeded thirty feet in length. 
There are seven or eight known species of 
the genus Ichthyosaurus, all agreeing with one 
