22 INTEODDCTION. 



Order 4. Oanoidei. — Ex. Bony Pike (Lepidosteus), Paddle -fish 



(Spatularia), Sturgeon (Sturioj. 

 Order 5. Elasmohranchii. — Ex. Sharks (Carcharida;), Dog-fishes 

 (Scylliadje), Saw -fishes (Pristis), Eays and Skates 

 (Raiidfe). 

 Order 6. Dipnoi. — Ex. Mud-fish (Lepidosiren). 

 Class II. Amphibia (Amphibians). — ^Breathing-organs in the young in 

 the form of gills alone, afterward lungs, either alone or associated with gills. 

 Skull jointed to the backbone by two articulating surfaces (" condyles "). 

 Limbs never converted into fins. Heart in the young of two chambers 

 only, in the adult of three chambers. Blood cold. 

 Order 1. LahyriTdlwdontia (extinct). 

 Order 2. Ophiomorpha. — Ex. Ctecilia. 



Order 3. Urodela (Tailed Amphibians). — Ex. Water-newts (Triton), 

 Salamanders (Salamandra), Axolotl (Siredon), Mud-eel 

 (Siren\ 

 Order 4. Anoura (Tailless Amphibians). — Ex. Frogs (Rana), Tree- 

 frogs (Hyla), Toads (Bufo), Surinam Toads (Pipa). 

 Class III. Reptilia (Reptiles). — Respiratory organs in the form of lungs, 

 never in the form of gills. Heart three-chambered, rarely four-chambered, 

 the pulmonary and systemic circulations always connected together directly, 

 either in the heart itself or in its immediate neighborhood. Blood cold. 

 Skull jointed to the backbone by a single articulating surface or "condyle." 

 Each half of the lower jaw composed of several pieces. Appendages of the 

 skin in the form of scales or plates. 



Order 1. Chelonia. — Ex. Turtles (Cheloniid)£e, Soft Tortoises (Trio- 

 nycidffl), Terrapins (Emydidse), Land Tortoises (Tes- 

 tudinidss). 

 Order 2. Opliidia. — Ex. Vipers (Viperidae), Rattlesnakes (Crota- 

 lidse). Sea-snakes (Hydrophid^), Boas and Pythons 

 (Boidae). 

 Order 3. Lacertilia. — Ex. Lizards (Lacerta), Iguanas (Iguanidae), 



Monitors (Varanidae), Chameleons (Chameleontidas). 

 Order 4. Crocodilia. — Ex. Crocodiles, Alligators, Gavials. 

 Order 5. Ichihycypierygia (extinct). — Ex. Ichthyosaurus. 

 Order 6. SauropUrygia (extinct). — Ex. Plesiosaurus. 

 Order 7. Pterosauria (extinct). — Ex. Pterodactylus. 

 Order 8. Anomodontia (extinct). — Ex. Dicynodon. 

 Order 9. Deinosauria (extinct). — Ex. Iguanodon. 

 Class IV". Avbs (Birds). — Respiratory organs in the form of lungs, never 

 in the form of gills. Lungs connected with air-receptacles placed in different 

 parts of the body. Heart four-chambered. Blood warm. SkuU connected 

 with the backbone by a single articulating surface or " condyle." Each 

 half of the lower jaw composed of several pieces. Appendages of the skin 

 in the form of feathers. Cavities of the chest and abdomen not separated 

 by a complete partition (diaphragm). Fore-limbs converted into wings. 

 Animal oviparous. 



Order 1. TVo/atores (Swimmers). — Ex. Penguins (Spheniscida;), Gulls 

 (Larida2), Ducks (Anatidae), Geese (Anserinae), Flamin- 

 gos (PhffinicopteridEe). 

 Order 2. Orallatores (Waders).— £i:. Rails (Rallida;), Water-hens 

 rGalIinula3), Cranes (Gruidae), Herons (Ardeidse), Storks 

 (Ciconinas), Snipes and Woodcock (ScolopacidEe), Plovers 

 Oyster-catchers, and Turnstones (Charadriidai). 



