THE VERTEBRATA 237 



CLASS: AMPHIBIA. 



ORDER i. STEGOCEPHALIA (with armoured skulls), 

 Carb.-Perm. 



2. URODELA (newts), Lower Cret.-Rec. 



3. GYMNOPHIONA or CCECILIA (snake-like), Recent 

 only. 



4. ANURA (frogs), Eoc.-Rec, 



CLASS: REPTILIA. 



ORDER i. ANOMODONTIA or THEROMORPHA (related to 

 Stegocephalia on the one hand and Mammalia on the 

 other). The dominant land-animals of the Permian 

 period, especially in the Southern Hemisphere. Perm- 

 Trias. 



2. CHELONIA (tortoises and turtles), Trias.-Rec. 



3. ICHTHYOPTERYGIA (ichthyosaurs), Trias. -Cret. 



4. SAUROPTERYGIA (plesiosaurs, swimming reptiles, 

 less fish-like in aspect than the ichthyosaurs), Trias.-Rec. 



5. RHYNCHOCEPHALIA (lizard - like, with biconcave 

 vertebrae, two rows of teeth in upper jaw, between which 

 the single row of lower jaw bites, all teeth fused to the 

 bones : the sole modern survivor, Hatttria, is confined 

 to a few of the smaller islands of New Zealand), 

 Perm.-Rec. 



6. SQUAMATA (lizards and snakes), Upper Jur.-Rec. 



7. DINOSAURIA (the dominant land-animals of the 

 Mesozoic after the anomodonts had decayed; a very 

 varied series, showing considerable adaptative radiation ; 

 some, as Diplodocus and Iguanodon, attained a great size ; 

 related to crocodiles and birds), Trias.-Cret. 



8. CROCODILIA (crocodiles ; the earlier forms were 

 marine), Trias.-Rec. 



9. AVES (birds), Upper Jur.-Rec. 



10. ORNITHOSAURIA (pterodactyls), Jur.-Cret. 



