196 ILLINOIS BIOLOGICAL MONOGRAPHS [434 



SUMMARY 



1) All species of Myxosporidia which have been observed in various 

 parts of the world, reaching 237 in number, are recorded with figures. 



2) A new classification of Myxosporidia is proposed after discussion 

 of those of previous authors. 



3) A complete list of the specific names of the hosts that harbor Myxo- 

 sporidia, is given together with the names of the organ of infection and 

 the localities from which recorded. 



4) By study of the geographical distribution of Myxosporidia, it 

 is shown that few species are common both to American and European 

 waters or Asiatic and European waters, while the majority of Myxosporidia 

 are localized in definite and limited regions. 



5) The study of the organal distribution of Myxosporidia in the host, 

 shows that the gall-bladder is the organ most frequently invaded by the 

 parasite. The kidney, branchia and urinary bladder have less chances of 

 being attacked. 



6) One new genus, Wardia, is established. 



7) Nine new species; Wardia ovinocua, Mitraspora elongata, Chloromy- 

 xum trijugum, Chloromyxum catostomi, Myxidium americanum, Myxobolus 

 orbiculatus, Myxobolus discrepans, Myxobolus mesentericus and Henneguya 

 mictospora, are described from fresh-water fish collected in the vicinity 

 of Urbana, 111. 



8) Six new species; Sphaerospora carassii, Myxidium kagayafnai, 

 Myxobolus misgurni, Myxobolus miyairii, Myxobolus koi and Henneguya 

 miyairii, are recorded from fresh-water fish of Nippon. 



9) One new species; Chloromyxum wardi, is described from Alaska. 

 This is the second species of Myxosporidia from that part of North America. 



10) Keys to the genera and species of known Myxosporidia are in- 

 cluded. 



