EXTINCT ANIMALS 



the brain-case (on a level with the letter P). 

 This is called the " parietal foramen," and is 

 a fair-sized hole in which was lodged an eye, a 



Fig. 167. — Photograph of the upper surface of the skull of an 

 Ichthyosaurus. On a level with the letter P in the middle 

 of the skull is seen an oval pit, the " parietal foramen " in 

 which was lodged the " third " or " pineal " eye. 



third eye called the pineal eye. This eye is 

 found in some other reptiles also, and especially 



22S 



