advanced
Calkins, The Protozoa. Macmillan Company.
Jennings, Study of the Lower Organisms. Carnegie Institution Report.
Parker, Lessons in Elementary Biology. The Macmillan Company.
Wilson, The Cell in Development and Inheritance. The Macmillan Company.
XIV. DIVISION OF LABOR. THE VARIOUS FORMS OF PLANTS AND ANIMALS
Problems.—The development and forms of plants.
The development of a simple animal.
What is division of labor? In what does it result?