ROLL CALL ,„y 



Super-Class C — Tetrapoda — Four-footed vertebrates. 



Characteristics : Well-defined limbs witli hands and feet typically con- 

 structed on plan of five digits; stapes or coluniolla present in ear; Rirdles 

 adapted to bear weight on land; body divisible into neck and trunk, tail 

 present. 



Class I — Amphibia — Frogs and salamander.'?. 



Characteristics: Cold-blooded, naked vertebrates undergoing a meta- 

 morphosis ; usually with five-fingered limbs (pentadactylous) ; young 

 u.sually aquatic, breathing by gills; adults using lungs and skin, u-suallj' 

 air breathers. 

 Order 1 — Stegoccphalia — Extinct fossil amphibians (Erynps, Loxomma). 



Ch.^racteristics : Fossil forms resembling amphibia, flourishing in car- 

 boniferous age ; probably earliest four-footed air breathers. 

 Order 2 — Apoda — Legless amphibia (Herpeles, Siphonops, Caecilia). 



Characteristics : Small, tropical, wormlike, often blind amphibia, burrow- 

 ing in ground. 

 Order 3 — Urodela — Salamanders {Desmognathus, Necturus, Cryptobranchus, 

 Triturus). 

 Characteristics: Tadpole-like tail retained throughout life; some never 

 emerge from water; a few retain external gills in adult stage. 

 Order 4 — Anura — Frogs and toads {Rana, Bufo, Ilyla). 



Characteristics : Tailless upon completing their metamorphosis ; capable 

 of singing ; characterized by the possession of movable eyelids. 



