THE CHROMOSOMES 



117 



and on the other side hybrid in character and 

 probably came from such half -fertilized eggs. It 

 will be recalled that Baltzer has shown that when 

 the cross is made in this direction both paternal and 



FIG. 40. 1, The chromosomes of the egg lie in the equator of the 

 spindle, the chromosomes of the sperm at one side; 2, a later stage show- 

 ing all of the paternal chromosomes lying at one side passing to one pole; 

 3 (to the right), later stage;the conditions are the same; there is also a 

 supernumerary sperm in the egg (shown to the left, in another section); 

 4, same condition as last; 5, pluteus larva that is purely maternal on one 

 side, and hybrid on the other. (After Herbst.) 



maternal chromosomes behave normally at each 

 division. The conclusion follows with much plausi- 

 bility that the absence of paternal characters on one 

 side is due to the absence of paternal chromosomes 

 on that side. 



