MYXOSPORIDIA 



I0 7 



occurrence of numerous nuclei. Recently the following authors have 

 contributed important additions to our knowledge of th? myxosporidia : 

 Perugia (9), Thelohan (10), Mingazzini (n), L. Pfeiffer (12), L. Cohn 

 (13), and Donein(i4); while the presence of this parasite outside ^the 

 class of fishes has become known through Lutz, Laveran, and", others. 



a. b. c. d. 



FIG. 47. Part of a gill of 

 Leuciscus vutilus, (natural size), 

 with two myxosporidia (a, b, d) 

 Spores of myxosporidia from 

 Esox lucius (c) Spores from 

 Platystoma fasciatum (after J. 

 Miiller). 



a b 



FIG. 48. (a) Myxobolus 

 Mulleri, Biitschli, on the lobe 

 of the gill of a cyprinoid ; (b) 

 the tailless spore, with the 

 polar bodies and their nuclei 

 and the sporozoite (after 

 Biitschli). 



The species causing diseases in fishes have been described by Ludwig 

 (15), Railliet (16), Weltner (17), L. Pfeiffer (12), Zschokke (18), Hofer (19), 

 Doflein (14), Gurley (20), and in regard to classification the works of 

 Thelohan (21) and Gurley (22) may be mentioned. The myxosporidia live 

 either free on the epithelial surfaces of hollow organs (gall or urinary bladder, 



FIG. 49. (a) Myxidium Lieberkuhnii B., 

 from the urinary bladder of Esox lucius ; (&)a 

 pansporoblast ; (c) complete spore (after 

 Biitschli). 



b. 



renal tubules, but never in the intestine), or are enclosed in the tissues of 

 their host. The gills and muscular system are their favourite habitat but 

 other tissues or organs, with the exception of the bones and cartilages, are 

 apt to be attacked. 



The free forms move with the assistance of variously shaped pseudo- 

 podes, have a constant form, or may exhibit contractions of the body ; 



