THE ICHTHYOSAURUS. 151 
the Zoological Gardens. Having said thus much I will briefly 
refer to the various organs of the Ichthyosaurus and show how 
it has been possible to give you its likeness. 
The head resembles that of a lizard or crocodile, the fore part 
of it being like that ofa porpoise. It was of an enormous size, in 
Jarge specimens reaching a length of five or six feet. The teeth 
are conical, similar in shape to those of a crocodile, but not 
having sockets,—they were arranged in a ridge along the inside 
of the jaw. Ample provision was made for their continual 
renewal, a new tooth being constantly growing at the base of the 
old one; the number reached in some cases to 180. But the 
head differed from that of a crocodile in the position of the 
nostrils ; the crocodile has them at the extremity of the head, the 
Ichthyosaurus had them just in front of the eye, as you may see 
in the little lizard so plentiful on our heaths. This shows a close 
connection with the lizard tribe, and the teeth prove it to be 
carnivorous. The most striking feature in the head is the eye, 
which equalled in size the human head and had an aperture 12 
to 14 inches across. This enormous size would enable it to take 
in a proportionate quantity of light, a power which of course 
gave it a better opportunity of seeing its prey, especially in deep 
water where little light penetrated. The opening of the pupil 
was surrounded by a series of thin bony plates, by means of 
which the aperture could be contracted or expanded, and so the 
animal might adapt its sight to objects far off or near at hand. 
There is a similar arrangement in the eyes of turtles, lizards, and 
some of the birds of prey, but it is never found in fishes. Here 
we see, then, how the teeth and the eyes correspond, and we 
also begin to see that the animal was not a fish. AsI have 
spoken of the teeth I may as well in this place finish what I have 
to say about the food of the ichthyosaurus. The teeth show it 
to have been carnivorous, but the question has been settled 
beyond all doubt, owing to the wonderful preservation of some 
of the specimens. One was found in the Lyme Regis quarries 
in which the contents of the stomach were fossilised inside the 
body ; among them were bones and scales of fishes and reptiles, 
