X 



15. 



Phylum Annelida. Seg- 

 mented Worms 



16. Phylum Arthropoda. 

 Crayfish, Crabs, Barna- 

 cles, Water Fleas, Sow 

 Bugs, and Others 



17. Phylum Arthropoda. Pe- 

 ripatus. Centipedes, and 

 Millipedes 



18. Phylum Arthropoda. In- 

 sects 



19. Phylum Arthropoda. 

 Spiders and Their Allies 



20. Phylum Mollusca. Snails, 

 Squids, Octopuses, and 

 Others 



21. Phylum Echinodermata. 

 Starfishes, Sea Urchins, 

 Sea Cucumbers, Sea 

 Lilies, and Others 



22. Phylum Chordata. Am- 

 phioxus, Tunicates, Verte- 

 brates, and Others 



23. A Representative Verte- 

 brate. Frog 



24. Class Agnatha (Jawless 

 Vertebrates). Lampreys 

 and Hagfishes 



25. Class Chondrichthyes. 

 Cartilaginous Fishes 



CONTENTS 



26. Class Osteichthyes. Bony 



170 Fishes 378 



27. Class Amphibia. Frogs, 

 Toads, Salamanders, and 

 Others 396 



197 



222 



315 



326 



360 



368 



28. Class Reptilia. Turtles, 

 Lizards, Snakes, Croco- 

 diles, and Others 405 



29. Class Aves. Birds 432 



228 30. Class Mammalia. Mam- 

 mals 463 



267 31. Skeletal Systems and 



Movement 498 



32. Metabolism and Trans- 



281 port in Animals 509 



33. Coordination and Be- 

 havior 543 



303 ^^* Reproduction and Devel- 

 opment 558 



35. Heredity 



38. History of Zoology 

 Glossary 



572 



36. The Origin and History of 

 Animal Life 601 



37. Ecology and Zoogeogra- 

 phy 628 



Index 



652 

 661 

 691 



