No. 612] MYXOSPOBIDIAN LIFE 



723 



myxum, and Henneguya. The reduction consisting in the 

 transformation of a diploid nucleus into a haploid or of a 

 tetraploid one into a diploid can only occur at the begin- 

 ning of the new life cycle after or before the union of the 

 gametonuclei. 



The further facts which Davis, 1915, presents in Sphce- 

 rospora dimorpha also tend to show that reduction 

 could only take place at the above outlined place. The 

 gametonuclei of this myxosporidian fuse together after 

 it leaves the spore and form by one subsequent division 

 tivo nuclei. One of these nuclei gives rise to all the 

 cells of the later sporogenous body. The other of these 

 two nuclei, distinguished by its size and structure, is 

 the vegetative nucleus of the animal, the somatic ''Rest- 

 kern." No other nuclei should be called ''Restkerne" 

 except ivhen they represent the nucleus or nuclei of the 

 vegetative myxosporidian body, uhich does not play a 

 part in spore formation. Such "Eestkern" or ''Rest- 



TABLE I 







m 



is 



i 



IE-; 



8. Auerbach... 



ill 



5 



observed 'in 'his 

 mono-, di- and 



I 





