206 THE BIOLOGY OF THB ANIMAL 



frogs to find decided variations in shape. Is the 

 shape of the body adapted to the frog's mode of 

 life? 



h. Size. — "What is the length of your specimen ? "Width ? 

 "Where is the place of greatest width ? Of least 1 

 "Where that of greatest depth ? Least? 



c. Color. — "What is the genei'al color of the body ? Do 



you find decided differences between the colors of 

 the dorsal and ventral surfaces ? "What colors do 

 you find on the dorsal surface? How are they 

 arranged? Is the disposition of colors on the 

 right the same as that on the left side ? Examine 

 a number of frogs and see whether or not they 

 are colored alike. Do all show the same arrange- 

 ment and the same shades of color? Can you 

 give any reasons for the presence and distribution 

 of the colors found ? If practicable, examine the 

 same frog at different seasons of the j^ear to see 

 whether or not there be any variation in the color 

 of a single individual. 



d. General Structure. — Ifote that the entire body con- 



sists of an axial portion, composed of head 

 and trunk ; and an appendicular portion, the 

 limbs. Study the skin covering the body. What 

 is its texture ? Is it closely fastened to the un- 

 derlying parts? Does it vary in this respect? 

 Does it bear any outgrowths, as scales, hairs, 

 feathers, etc. ? 

 1. The head. — "What is its shape as seen from 

 above? From the side? Is it connected to 

 the body by a neck ? How do you distinguish 



