THE JURASSIC PERIOD 



233 



Reptiles. — Viewed in the broadest way, the Reptiles of the 

 Jurassic were much like those of the Triassic, except that they 



Fig. 145 



Three stages in the life history of a modern Crab. The 



larval stage B is very similar to the adult Jurassic form 



shown in figure 144. (After Couch, from Le Conte's 



"Geology," permission of D. Appleton and Company.) 



became more numerous and diversified. By some, this period is 

 regarded as the culminating time of the Reptiles. As compared 



Fig. 146 



A primitive or ancestral Jurassic Teleost, Hypsocormus insignis. (From 



Scott's "Geology," courtesy of The Macmillan Company.) 



with the Triassic all the same principal groups were still repre- 

 sented, though with many genera and species changes. The more 



