MYXOSPORIDIA 315 



For thirty days, almost all the spores thus preserved were capable 

 of filament extrusion upon addition of a drop of potassium hydrate 

 solution (thirty-five per cent). At the end of two months, complete 

 filament extrusion was noted in numerous spores when treated 

 in a similar manner. From that time on, the number of spores 

 which were able to protrude their polar filaments decreased, and 

 at the end of nearly five months, about fifty per cent of the spores 

 examined, extruded "short and not fully extended'' filaments under 

 the influence of the potassium hydrate solution. In preserved 

 spores, the length of the polar filament should, therefore, be bet- 

 ter calculated by counting the number and measuring the diam- 

 eters of the coils of the filament within the polar capsule. 



The remaining part of the material should be made into smears 

 and sections and studied as was stated above for the fresh 

 material. 



PROBLEMS 



1. Improved classification. The present system of classification 

 of the MYXOSPORIDIA, as outlined elsewhere, appears to be better 

 fitted for our present state of knowledge of this group than any 

 other (Kudo, 1920; Calkins, 1926; Wenyon, 1926). Increase of 

 our knowledge of these organisms would without doubt result in 

 bringing out a better and more natural classification than the pres- 

 ent one. 



2. Phylogcny of the Myxosporidia. Some attempts were made 

 to consider the phylogenetic relation of myxosporidia to other 

 groups of animal kingdom. Emery (1909), Ikeda (1912) and 

 others, pointed out that the spore of myxosporidia and especially 

 of actinomyxidia, an allied group, resembles the ciliated stage 

 of Dicyerna, a mesozoan, in that each possesses protective cells 

 within which are present reproductive cells. 



3. lodinophilous vacuole. The writer treated the spores of three 

 species of Myxohohis and of two species of Henneguya with 

 various glycogen-testing methods, and came to the conclusion that 

 the vacuole contained a substance whose chemical reactions were 

 similar to those of glycogen (Kudo, 1921). It is generally under- 

 stood without any experimental evidence that the glycogen is 

 probably used in the future development of the sporoplasm. 



4. Status of various genera. The existing genera are not well 

 dififerentiated. The genera Myxosonia and Lentospora should pos- 

 sibly be united under the former, since the difiference noted be- 



