168 ANIMAL LIFE 
88. Division of labor and basis of communal life-—We have 
learned in Chapters II and IV that the complexity of the 
bodies of the higher animals depends on a specialization or 
differentiation of parts, due to the assumption of different 
functions or duties by different parts of the body; that the 
degree of structural differentiation depends on the degree 
or extent of division of labor shown in the economy of the 
animal. It is obvious that the same principle of division of 
labor with accompanying modification of structure is the 
basis of colonial and communal life. It is simply a mani- 
festation of the principle among individuals instead of 
among organs. The division of the necessary labors of life 
among the different zoojds of the colonial jelly-fish is plain- 
ly the reason for the profound and striking, but always 
reasonable and explicable modifications of the typical polyp 
or medusa body, which is shown by the swimming zooids, 
the feeding zooids, the sense zooids, and the others of the 
colony. And similarly in the case of the termite commu- 
nity, the soldier individuals are different structurally from 
the worker individuals because of the different work they 
have to do. And the queen differs from all the others, be- 
cause of the extraordinary prolificacy demanded of her to 
maintain the great community. 
It is important to note, however, that among those ani- 
mals that show the most highly organized or specialized 
communal or social life, the structural differences among 
the individuals are the least marked, or at least are not the 
most profound. The three kinds of honey-bee individuals 
differ. but little; indeed, as two of the kinds, male and 
female, are to be found in the case of almost all kinds of 
animals, whether communal in habit or not, the only unu- 
sual structural specialization in the case of the honey bee, is 
the presence of the worker individual, which differs from 
the usual individuals- in. but little more than the rudimen- 
tary condition of the reproductive glands. Finally, in the 
case of man, with whom the communal or social habit is so 
