PHENOMENA ACCOMPANYING FERTILIZATION 323 



(Fig. 163, B). Two such amebae become enclosed in a common cyst 

 but do not fuse. According to Hartmann and Nagler, the two 

 amebae are products of division of one ameba, the apposed nuclei 

 of each organism then fuse into one. This fusion is followed by two 

 reduction divisions of the fused nuclei, three of the products degen- 

 erating. Two amebae then fuse again and their nuclei come 

 to lie side by side. The question of autogamy obviously depends 

 upon the origin of the two amebae in the common cyst. If they 



Fig. 163. — Sappinia diploidea. The ordinary vegetative individual has two nuclei 

 which divide independently at cell division. With encystment these nuclei form 

 spindles (B) and the cells divide (C, D); the two pairs of nuclei then unite, forming 

 two fusion nuclei after which the cell bodies reunite, thus forming the vegetative 

 binucleated cell. (After Hartmann and Nagler.) 



do not come from the same parent cell, the phenomenon is one of 

 delayed exogamy. 



Autogamy appears to be characteristic of the Neosporidia among 

 the Sporozoa and the processes are fairly uniform in Myxosporidia, 

 Microsporidia and Actinomyxida. Multinucleate cells are typical 

 of the nutritive or vegetative stage and in some cases the nuclei are 

 dimorphic. Spores are formed endogenously and during the con- 

 tinued vegetative activity of the organism. The process was well 



