660 PROTOZOOLOGY 



M. intestinalis K. (Fig. I, a). In the intestinal wall of Pomoxis 

 sparoides; (fixed unstained) spores, 12-13/x by 10-12.5/x; the his- 

 tological changes brought about by this protozoan have been men- 

 tioned elsewhere (p. 27) (Kudo, 1929). 



M. squamosus K. (Fig. 285, l-o). In connective tissue below scales 

 of Hybopsis kentuckiensis; spore circular in front view, 8-9/x in 

 diameter, 4.5-5m thick. 



Genus Thelohanellus Kudo. Pyriform spores, each with one polar 

 capsule; sporoplasm with an iodinophilous vacuole; histozoic in 

 freshwater fish. 11 species (Kudo, 1933). 



T. notatus (Mavor) (Figs. 1, 6; 285, c, d). In subdermal connective 

 tissue of Pimephales notatus, Cliola vigilax, Notropis cornutus, N. 

 blennius, and Leuciscus rutilus; tumor up to 7 mm. in diameter; 

 spores 17-18m by 7.5-10m; host tissue surrounding the organism be- 

 comes so greatly changed that it appears as an epithelium (p. 31) 

 (Debaisieux, 1925; Kudo, 1929, 1934). 



Genus Henneguya Thelohan (Myxobilatus Davis). Spore circular 

 or ovoidal in front view; flattened; 2 polar capsules at anterior end; 

 each shell-valve prolonged posteriorly into a long process; sporoplasm 

 with an iodinophilous vacuole; mostly histozoic in freshwater fish. 

 Numerous species. 



H. exiles Kudo (Figs. 278; 285, p-r). In gills and integument of 

 Ictalurus punctatus; cysts up to 3 mm. in diameter, conspicuous; 

 spores, total length 60-70/x, spore proper 18-20/x long by 4-5/x wide 

 by 3-3.5m thick (Kudo, 1929, 1934). 



H. mictospora Kudo. In the urinary bladder of Lepomis spp. and 

 Micropterus salmoides; spores 13.5-15m long, 8-9m wide, 6-7.5m 

 thick; caudal prolongation 30-40/x long. 



Genus Unicauda Davis. The spore is similar to that of Henneguya, 

 but the single caudal appendage is not an extension of the shell- 

 valves. Several species (Davis, 1944). 



U. clavicauda (Kudo) (Fig. 285, s-u). In the subdermal connective 

 tissue of the minnow, Notropis blennius; oblong or ellipsoid cysts, 

 1-1.5 mm. in the longest diameter; spores 10.5-11. 5/x by 8. 5-9. 5m by 

 6m; appendage 20-30m by 3-6.5m (Kudo, 1934). 



Order 2 Actinomyxidia Stole 



The Cnidosporodia placed in this order have been less frequently 

 studied and, therefore, not so well known as the Myxosporidia. The 

 spore is enveloped by a membrane, or shell composed of 3 valves 

 which are sometimes drawn out into simple or bifurcated processes. 

 There are also 3 polar capsules in the spore and the polar filaments 



