348 



CONTENTS. 



PAGE 



III. The Foregoing Considerations applied to the Male 



Germ-cells ......... 381 



The male germ-cells also require division in order to reduce 



the ancestral germ-plasms ...... 381 



The germ-plasms of the parents must be contained in the 



germ-plasm of the offspring ...... 382 



Advantages which the egg gains by the late occurrence of 



the ' reducing division ' . . . . . . . 883 



The causes of unequal division in the formation of polar 



bodies 385 



These causes do not apply to the sperm-cell . . . 385 



Different kinds of nuclear division occur in spermatogenesis 386 



Some of these may be interpreted as ' reducing divisions ' 

 The paranucleus ('Nebenkern ') of spermatogenesis probably 

 contains the histogenetic nucleoplasm . 



IV. The Foregoing Considerations applied to Plants 

 V. Conclusions as regards Heredity 



The germ-cells of an individual contain different combina- 

 tions of hereditary tendencies .... 

 Dissimilarity between the offspring of the same parents 

 Identity of twins produced from a single egg 



VI. Recapitulation ........ 



387 



388 

 388 

 390 



390 

 391 

 392 



394 



