BILATERAL, OR TWO-SIDED, SYMMETRY^ 



The three "faces" are of the same person. The middle is a normal full-face photo- 

 graph. The first is made up of the right half of the face and a "mirror image" of the 

 same. The third consists of the left half with its "mirror image" 



We might say of such plants, (1) their bodies consist of distinct parts, 

 and (2) the parts undergo orderly changes in the course of the year. 



The Human Body Since we are most familiar with our own bodies, 

 we naturally use the body as a standard for judging other living things, or 



Bear 



Man 



I 



1 \ 



Kangaroo 



BODY PLAN OF MAMMALS 



In all these animals there is a main axis, with the head at the front end. There are 

 two pairs of limbs — the front ones attached at the "shoulders" and the hind ones 

 attached at the "hips" 



^From Expression of Personality by Werner Wolff. By permission of Harper & Brothers. 



13 



