312 



REPRODUCTION IN ANIMALS 



separated so that each resultant germ cell of the second 

 order contains one member of each pair. But whether 

 this member was derived from the sperm or the egg at 

 the time of fertilization, that is, whether it is paternal 



Fifj. 76. -^ Diagram illustrating the reduction of the chromosomes. 

 A, nucleus of sperm mother cell, with 8 chromosomes. B, pairing 

 of chromosomes. (7, divi.sion of sperm mother cell, showing 4 chro- 

 mo.somes passing into each daughter cell. />, four immature sperms, 

 each with 4 chromosomes, resulting from two divisions of the sperm 

 mother cell. 



or maternal, is a matter of chance. In other words, the 

 thousands of sperm mother cells produce, in the species 

 under discussion, sixteen different types of sperm cells 

 depending upon their chromosomes. If letters are used 



