Fig. 23-3 Regular first-division segregation of mating type 

 alleles and regular orientation of spindles in Neurospora tetra— 

 sperma combining to produce spores all of which contain four 

 nuclei, two each of opposite mating type (copied from Dodge). 



<^Z2> 



Fig. 23-4 Copulation in Saccharomycodes. (Copied from 

 Winge and Laustsen). 



23-3 



