REPRODUCTION 



151 



Fig. 75. The life-cycle of Nyctotherus cordiformis in Hijla versicolor 

 (Wichterman). a, a cyst; b, excystment in tadpole; c, d, division is 

 repeated until host metamorphoses; e, smaller preconjugant; f-j, con- 

 jugation; k, exconjugant; 1, amphinucleus divides into 2 nuclei, one 

 micronucleus and the other passes through the "spireme ball" stage 

 before developing into a macronucleus; k-n, exconjugants found 

 nearly exclusively in recently transformed host; o, mature trophozoite; 

 p-s, binary fission stages; t, precystic stage. 



