92 



THEORY OF EVOLUTION 



a 



d 



At 



e 



Fig. 46. A .series of cells in process of cell division. The 

 chromosomes are the black threads and rods. (After 

 Bahlgren.) 



set of students who have worked in an entirely 

 different field. Certain observations and ex- 

 periments that we have not time to consider 



