Fig. 32-39. The seven vertebrate classes. A, Cyclostomata, a lamprey; B, Chondrichthyes, shark; C, Osteich- 

 thyes, sunfish; D, Reptilia, alligator; E, Aves, owl; F, Mammalia, deer; G, Amphibia, frog. (A, C, E, and F 

 by courtesy of Ohio Division of Wildlife Service; D, from Ward's Natural Science Establishment; and G, from 

 Edward S. Thomas. Composite from General Zoology, by Miller and Haub. Holt, Rinehart and Winston, Inc.) 



