v PLASMODIUM-FORMATION AND CONJUGATION 55 



plasmodi urn-formation and that of conjugation as seen in 

 Heteromita. Two Heteromitae fuse and form a zygote the 

 protoplasm of which divides into spores. In Protomyxa and 

 the Mycetozoa not two but several amoebulse unite to form 

 a plasmodium which after a time becomes encysted and 

 breaks up into spores. So that we might look upon the 

 conjugation of Heteromita as an extremely simple plasmo- 

 dial phase in its life-history, or upon the formation of a 

 plasmodium by Protomyxa and the Mycetozoa as a process 

 of multiple conjugation. 



There is, however, an important difference between the 

 two cases by reason of which the analogy is far from complete. 

 In Heteromita the nuclei of the two gametes are no longer 

 visible (p. 41) : they coalesce during conjugation, and 

 the product of their union subsequently, in all probability, 

 breaks up to form the nuclei of the spores. In the Myce- 

 tozoa neither fusion nor apparent disappearance of the 

 nuclei of the amcebulae has been observed. 



