306 HEREDITY IN THE PROTOZOA 
phrya, and in a few other forms, a similar reduction 
in the number of the chromosomes has been ob- 
served. It would seem more probable that we 
Fig. 72.—Two species of Chlamydomonas, A and B. AA and BB, 
conjugation cysts of A and B respectively. AB, hybrid cyst. a, b, ba, 
ab, types that develop from hybrid cysts. (After Pascher.) 
must look for reduction before nuclear interchange 
rather than after that event. Even then it has by 
no means been shown that reduction here means 
segregation, as in the higher forms, for the value 
