SURVEY OF VERTEBRATES 



119 



the gardener owes a Toad on his premises nearly twenty dollars 

 at the end of the season. Moreover, the Toad is much maligned 

 by having attributed to it the power to produce warts on the 

 human skin. 



Tree Frogs and Tree Toads are tiny arboreal forms with soft, 

 adhesive pads on the toe tips. Many of them, such as the common 



Fig. 78. -- A, Toad. Bufo americanus. stalking prey; B, Leopard Frog, 

 Rana pipiens; C, Javan Flying Frog. Rhacophorus pardalis; D. Tree Frog, 

 Hyla versicolor. (From Newman, after Dickerson and Lydekker.) 



Tree Frog, Hyla versicolor, are able to change their color through 

 various shades of gray, brown, and green, and so are rendered 

 inconspicuous in their natural surroundings. (Fig. 78.) 



The true Frogs are represented by several well-known species 

 in the United States: among them the Leopard Frog {Rana pipiens), 

 the Bull Frog (Rana catesbeiana), and the Green Frog (Rana clami- 

 tans). More need not be said about Frogs at this point because 

 they will be referred to again. As a matter of fact they are in 

 many ways ideal subjects for anatomical and physiological in- 

 vestigations and therefore have contributed considerably to the 

 advancement of biological science. (Figs. 107, 175.) 



