ICHTHYOSAURS AND COPROLITES 



in some of the living lizards where its structure 

 has been studied with the microscope. There 

 is no doubt that the body filling this hole in 

 living lizards is an eye, although it seems to 

 have lost the power of sight in these recent 

 forms. A third eye, placed on the top of the 

 head strikes one as a very strange arrangement 

 and contrary to all our common experience of 

 vertebrate animals. 



Fig. 168. — Side view of the skeleton of an Ichthyosaurus. 

 Below the skeleton is drawn a " coprolite " showing spiral 

 grooving on its surface. 



In Fig. 168 we have a drawing of the side 

 view of the skeleton of an Ichthyosaurus and 

 below it a fossilized lump of its excrement. 

 These are called coprolites and consist of scales 

 and bones of fishes digested by the Ichthyosaurus. 

 They show a corkscrew-like moulding of the 

 surface, proving that the intestine of the 



229 



