PRINCIPLES OF ANIMAL BIOLOGY 19 



of many-celled animals. What functions have been studied in each? 

 Is cooperation or division of labor involved in either case? The guide 

 questions throughout the exercise will suggest valuable comparisons. 



References 



HUXLEY, THOMAS H., "Lessons in Elementary Physiology." 

 JENNINGS, H. S., "Behavior of Lower Organisms."- 

 VERWORN, MAX, "General Physiology." 



