THE VERTEBRATE ANIMALS 



285 



REFERENCE BOOKS 

 ELEMENTARY 



Sharpc, A Laboratory Manual. American Book Company. 

 Davison, Practical Zoology, pages 1S5-199. American Book Company. 

 Herrick, Textbook in General Zoology, Chap. XIX. American Book Company. 

 Jordan, Kellogg, and Heath, Animal Studies, XIV. D. Appleton and Company. 



ADVANCED 



Jordan and Evermann, American Food and Game Fishes. Doubleday, Page, and 



Company. 



Jordan, Fishes. Henry Holt and Company. 



Kingsley, Textbook of Vtrt<-l>mt< Zoology. Henry Holt and Company. 

 Riverside Natural History. Houghton, Mifflin, and Company. 



Amphibia. The Frog 



Problem XXXVII. S<>nn< <ul dotations in a living frog. 

 (Laboratory Manual, Prob. .V.V.V/7J.) 



Adaptations for Life. The most common frog in the eastern 

 part of the United States is the leopard frog. It is recognized by 

 its greenish brown body with dark spots, each spot being outlined 

 in a lighter colored background. In spite of the apparent lack of 

 harmony with their sur- 

 roundings, their color, on the 

 contrary, appears to give 

 almost perfect protection. 

 In some species of frogs the 

 color of the skin changes 

 with the surroundings of the 

 frog, another means of pro- 

 lection. 



Adaptations for life in the 

 water are numerous. The 

 ovoid body, the head merg- 

 ing into the trunk, the slimy 

 covering (for the frog is pro- 

 vided, like the fish, with mucus cells in the skin), and the power- 

 ful legs with webbed feet, are all evidences of the life which the 

 frog leads. 



The leopard frog. 



