REPTILES IN GEOLOGY 



149 



The third one of these paddle- 

 limhed orders had bodies that were 

 snakelike with extremely long tails. 

 The type - form is the M(>f<a.saurus, 

 found fossil in the Old World ; but 

 America also is rich in them. Pro- 

 fessor Cope has called them Python - 

 omorpha. One of them — the Edesto- 

 saurus — is here shown (Fig. ^'^). It 

 will be noted that their limbs, while 

 paddlelike, had the digits more like 

 those of land -haunters. It can be seen 

 by the lengthened spines on the tail 

 vertebrae that the tail had a crest and 

 was a swimming organ. They are 

 much like serpents in some of their 

 parts. It was in these that the jaws 

 were doubly hinged for sw^allowing. 

 Many had more ribs than the one here 

 figured, and there was no breast-bone 

 meeting of ribs below. 



The next division is the great land- 

 haunting group known collectively as 

 Dinosaurs. It is supposed (and prob- 

 able) that the crocodilians lay between 

 the Ichthyosaurus and these. Here 

 Nature seemed to have tried all things 

 and hoped all things — holding fast to 

 nothing. We can note only a few 

 typical forms. 



While some were four-footed in 



^ 



