PROTOZOA 



125 



tending along the surface of the organisms or special organs for the 

 intake of food. 



Reproduction. — The protozoa reproduce in many different ways 

 and several of these ways may occur in a single organism. For this 

 reason, their reproductive power is very great; in power of repeating 

 their Hke, they fall just short of the bacteria'. The union of a male and 

 a female form does not always precede multipHcation; sexual union 



Fig. 92. — Stages in the division of Amceba polypodia. {After F. E. Sckulze and Lange 



from Doflein.) 



and reproduction, though now combined in many animals, may have 

 been originally two entirely distinct phenomena and, in the protozoa, 

 though sexual union may be concerned with the production of new 

 individuals, it is often especially associated with the regeneration of 

 the protoplasm of the parasites taking part in it. 



The simplest of the methods of reproduction is simpk binary divi- 

 sion, in which the organism divides into two equal parts. A modifica- 

 tion of this process is gemmulation, in which a small protozoon buds off 



