HEREDITY IN THE PROTOZOA 307 



of the individual chromosomes has not been demon- 

 strated. There is, it is true, one case at least — in 

 flagellates — in which the evidence seems to show 

 that segregation takes place after conjugation. It 

 has been shown by Pascher that when two species of 

 Chlamydomonas conjugate and then encyst (Fig. 72) 

 the resulting cj^st is unlike the cyst of either parent, 

 and may be said to be intermediate. While in the 

 cyst, a reduction division occurs, and four new 

 individuals emerge. These then multiply by fission. 

 The offspring show the parental characters combined 

 in different ways. Some of the individuals are like 

 the parent species, others show recombinations of 

 the original characters. The results, if confirmed, 

 furnish evidence of segregation, but the numerical 

 relations between the different types produced by 

 each cyst are unknown. 



