xli 



o. 



URINARY ORGANS. 



(Including Kidneys, Bladder, and Waste Products.) 



Chief duty the removal from the body of waste nitrogenous 

 matter (as Urea and Unites) and surplus water. 



The cells that excrete this product are usually derived from 

 those which line the body-cavity. 



Examples taxonomically arranged. They will sometimes include 

 the reproductive organs. 



P. 



SPECIALIZATION AND DIVISION OF LABOUR 

 AMONGST "PERSONS" OR "INDIVIDUALS." 



A mass of non-specialized protoplasm can perform all the 

 essential functions of life ; it can move, take in food and digest 

 it, grow by forming its own substance out of absorbed food which 

 was originally unlike itself (a function peculiar to living matter), 

 and can by division increase in number (e. ft. Rhizopoda). In 

 the Infusoria different layers of the protoplasm are specialized 

 to perform particular functions. 



The higher forms of animals (Metazoa) are composed of 

 numerous associated units (cells), each like the entire body of a 

 Rhizopod, and of tissues specialized to perform one function, 

 derived from such cells. We have here in the Metazoa a division 

 of labour amongst the cells and tissues. 



In the following examples we find a further division of labour, 

 certain semi-independent or independent "persons" produced 

 by budding from the organism resulting from the development 

 of one eggj or the different members of a colony of "indi- 

 viduals " take on the chief or exclusive performance of one 

 function. 



This division of labour is of the same advantage to the 

 members of a colony, as results from the special trades of 

 civilized life. 



