REPTILES IN GEOLOGY 



U9 



The third one of these paddle- 

 limbed orders had bodies that were 

 snakelike with extremely long tails. 

 The type - form is the Mosasaitriis, 

 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. 68). It 

 will be noted that their limbs, while 

 paddlelike, had the digits more like 

 those of land-haunters. It can be seeu 

 by the lengthened spines on the tail 

 vertebroe 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 swallowing. 

 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 thino-s 

 and hoped all things — holding fast to 

 nothing. We can note only a few 

 typical forms. 



AVhile some were four-footed in 



