722 



THE AMERICAN NATURALIST [Vol. LI 



I mentioned before that the glycogen which was found 

 in the vegetative body is used up in spore formation. 

 The membrane of the spore, the polar threads and the 

 darkly staining structureless lumps, which have been seen 

 by all authors inside the sporoblast, consist of glycogen 

 and stain as well by chromatin as by specific glycogen 

 stains. These lumps have been 

 considered as reduction nuclei" 

 by various authors. They have 

 also been called "Restkerne" or 

 ''residual nuclei." It may be 

 emphasized for later discussion 

 that they are glycogenous and 

 not chromatic in Chloromyxum 

 ley dig i. 



Our knowledge of the sexual 

 process in the myxosporidian life 

 cycle since the investigations of 

 Keysselitz, Schroeder, and others 

 has been completed by recent 

 authors: Georgevitch, 1914, 

 Davis, 1915 and Mavor, 1916. 

 The best proof that no reduction 

 takes place in the spore is given by Georgevitch (1914) 

 and Davis (1915), who have been able to study the num- 

 ber of chromosomes in their specimens before and after 

 spore formation. Both authors agree that the number of 

 chromosomes is not changed before and after this phe- 

 nomenon. Davis figures six chromosomes in Spharospora 

 dimorpha and Georgevitch, investigating Henneguya 

 gigantea, finds eight. These two facts: first, that the 

 number of chromosomes is not changed in spore forma- 

 tion and, second, that the so-called "reduction nuclei" 

 inside the spore are really glycogenous bodies which are 

 used up in forming the membrane of the spore, polar 

 threads, and spore membi-ane of Chlorowyjcum leydigi, 

 positively pi-ove that the real reduction must occur at a 

 different place in the life cycle of Sphcerospora, Chloro- 



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