32 GENERAL BIOLOGY 



cell " resulting from such a cleavage has half the 

 nuclear material of the original parent cell. In 

 this way the number of individuals is greatly in- 

 creased, and the continuity of existence of the race 

 of Amoebae insured. Such a function of reproduc- 

 tion also accounts for the great number of leucocytes 

 within the blood stream of an animal. Although 

 the details of the process are not known it is probable 

 that they are essentially similar to what has just 

 been described for Amoeba. 



These, then, seem to be primary functions of living 

 matter: contractility, assimilation, irritability, se- 

 cretion, and reproduction. Of nutrition and the phe- 

 nomena concerned with it we shall have more to say 

 in the next chapter. 



Specialization in Locomotor Organs. In but 

 few cells do we find the elementary functions of 



living matter so evenly 

 balanced and so little 

 specialized as in the 

 leucocyte and Amoeba. 

 The common form of 

 Amoeba just described 

 is called Amoeba pro- 



FIG. 10. Amoeba angulata (semi- t^US because of the 



diagrammatic), showing the antenna- f act t h at j t constantly 



like pseudopodium, a, which vibrates 



back and forth in the positions marked changes its shape, the 



production of pseudo- 



podia being urilocalized, as we have seen. In another 

 species of Amoeba, Amoeba angulata, there has been 



