MYXOSPORIDIA 323 



arrangement of chromatophores and becomes darkly colored. The 

 movement of such a fish is greatly affected. Since the myxospor- 

 idian attacks the cartilage of the auditory organ, the infected fish 

 loses its sense of equilibrium and this together with the twisted 

 hind part of the body results in a very peculiar turning movement 

 of the host fish. 



Phnephalcs notatiis of North America is strangely susceptible 

 to an infection of Myxobolus notatus (j\lavor, 1916, Kudo, 1929). 

 Debaisieux (1925) found an apparently similar species in Leucis- 

 cus rutilus of Belgium. In all cases the myxosporidian attacks the 

 subdermal connective tissue of the host fish only. The infected 

 tissue shows an abundance of blood capillaries. The tissue which 

 is in direct contact with the parasite appears to be an epithelial 

 tissue which was noted by all three workers. As to the origin of 

 this apparent "cell-layer," the writer showed that it is modified 

 connective tissue cells of the host, which change took place as the 

 result of myxosporidian stimulation (Kudo, 1929). 



14. Problems of ''diffuse infiltration." In numerous histozoic 

 MYXOSPORIDIA, there have been noted besides the cysts a number 

 of spores scattered in the adjacent connective tissue; i.e., the host 

 cells and myxosporidian spores intermingle with each other. The- 

 lohan (1895) noted this state and called it "parasitic" or "diffuse 

 infiltration." With regard to the modes of formation and signifi- 

 cance of such diffused state of infection in histozoic myxosporidia, 

 the main foci of infection of which are manifest in cystic form, a 

 number of opinions were advanced by Thelohan, Keysselitz 

 (1908), Auerbach (1912), Schuurmans-Stekhoven (1920), Kudo 

 (1926), etc. A better comprehension of this condition must depend 

 on future investigations. 



15. Problems of autoinfection. As to whether or not the spores 

 would germinate in the host body in which they developed or, in 

 other words, whether autoinfection of myxosporidia occurs or 

 not, there are two views: Pfeift"er (1888), Thelohan (1895), 

 Georgevitch (1914), Kudo (1920, 1926), Debaisieux (1922) and 

 others, considered that the spores would under certain circum- 

 stances germinate in the body of the host in which they developed 

 and give rise to new infection. On the other hand, one may suppose 

 that this is improbable since the germination of the myxosporidian 

 spore in the host organ other than the alimentary canal has yet 

 to be determined. 



