REPRODUCTION 



171 



individual through the unrestricted multiplication of 

 his component cells, and the perpetuation of the kind 

 must be secured through discontinuous growth i.e., off- 



Fia. 69. Conjugation of Paramoecium caudatum. [A-G, after R. Hertwig; 

 D-K, after Maupas.] (The macronuclei dotted in all the figures.) A, micro- 

 nuclei preparing for their first division; B, second division; G, third division; 

 three polar bodies or "corpuscules de rebut," and one dividing germ-nucleus 

 in each animal; D, interchange of the germ-nuclei; E, the same, enlarged; 

 F, fusion of the germ-nuclei; G, the same enlarged; H, cleavage-nucleus (c) 

 preparing for the first division; I, the cleavage-nucleus has divided twice; J, after 

 three divisions of the cleavage-nucleus; the macronucleus is breaking up; K, four 

 of the nuclei enlarging to form the new macronuclei. 



spring. In such animals it is not through the somatic 

 or general body cells, but through a certain few germ- 

 inal or reproductive cells, early set aside and highly 

 specialized for this purpose, that this is made possible. 



