840 APPENDIX 



Order 1. Dipnoi. The lungfishes. Epiceratodus of Australia, Protop- 



terus of Africa, Lepidosiren of South America. 

 Order 2. Crossopferygii. Crossopterygians. 



•f- Suborder 1. Rliipidistia. Fresh-water ancestors of amphibians. 

 Suborder 2. Coelacanthini. More specialized freshwater and marine 

 crossopterygians. Latimeria. 

 CLASS 5. AMPHIBIA. The amphibians. Larvae generally aquatic; adults ter- 

 restrial. 

 Subclass 1. Aspidospondyli. Vertebrae develop embryonically from cartil- 

 aginous rudiments, 

 t Labyrinthodonfia. A collective name for five orders of ancestral am- 

 phibians. 

 Order 6. Anura. The frogs and toads. The leopard frog, Rana; tree 

 frog, Hyla; American toad, Bufo. 

 Subclass 2. Lepospondvli. Vertebrae develop without cartilaginous rudi- 

 ment, 

 t Order 1. Microsauria. Ancestral lepospondyls. 

 Order 2. Urodela. The salamanders. The spotted salamander, Amby- 



stoiiui: redbacked salamander, Plethodoii; mudpuppy, Necturus. 

 Order 3. Apoda. The legless caecilians. 

 CLASS 6. REPTILIA. The reptiles: tetrapods that are covered with horny scales 

 and reproduce on the land. 

 Subclass 1. Anapsida. Primitive reptiles. 



t Order 1. Cotylosauria. The cotylosaurs, the ancestral reptiles. 

 Order 2. Chelonia. The turtles. Red-eared turtle, Pseudemys; green 

 sea turtle, Chelonia; side-necked turtle, Chelodina. 

 f Subclass 2. Eurvapsida. Ancient marine reptiles that propelled themselves 

 with paddles, 

 t Order 1. Sauropterygla. The plesiosaurs. 

 t Subclass 3. Ichthyoptervgia. Ancient, marine, fishlike reptiles, 

 t Order 1. Ichythyosauria. The ichthyosaurs. 

 Subclass 4. DLVPsmA. The most abundant reptiles. 

 Superorder 1. Lepidosauria. Lizard-like reptiles, 

 t Order 1. Eosuchia. Ancestral lepidosaurians. 

 Order 2. Rhynchocephalia. Primitive lizard-like reptiles. The tuatara, 

 Splteuodon. 



Order 3. Squamata. Lizards and snakes. 



Suborder 1. Lacertilia. Lizards. The collared lizard, Crotaphytus; 



horned toad, PInynosoma: Gila monster, Heloderma. 

 Suborder 2. Ophidia. Snakes. The Garter snake, Thamnophis; 

 water snake, Natrix; rattlesnake, Crotalus. 

 Superorder 2. Archosauria. The ruling reptiles, 

 t Order 1. Thecodonfia. Ancestral archosaurs. 



t Order 2. Saurischia. Saurischian dinosaurs: Tyrannosaurus, Bronto- 

 saurus. 



t Order 3. Ornithischia. Ornithischian dinosaurs: Stegosaurus, Tricera- 

 tops. 



t Order 4. Pterosauria. The flying reptiles: Pteranodon. 

 Order 5. Crocodilia. Alligators and crocodiles: the American alligator, 

 Alligator; American crocodile, Crocodilus. 

 t Subclass 5. Svnapsida. The mammal-like reptiles. 



t Order 1. Pelycosauria. Early mammal-like reptiles: Dimetrodon. 

 t Order 2. Therapsida. Later mammal-like reptiles: Lycaenops. 



