468 PROTOZOOLOGY 



M. intestinalis K. (Fig. 1, o). 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 

 mentioned elsewhere (p. 26). 



M. squamosus Kudo (Fig. 216, Ir-o). In connective tissue below 

 scales of HyJjopsis kentuckiensis ; spore circular in front view, 8- 

 9m in diameter, 4.5-5m thick. 



Genus Thelohanellus Kudo. Pyriform, flattened spores, each 

 with one polar capsule; sporoplasm with an iodinophilous vacu- 

 ole; histozoic in freshwater fish. 11 species. 



T. notatus (Mavor) (Figs. 1, h; 216, c, d). In subdermal connec- 

 tive tissue of Pimephales notatus, Cliola vigilax, Notropis cornu- 

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

 diameter; spores 17-18^ by 7.5-10/x; host tissue surrounding the 

 organism becomes so greatly changed that it appears as an epi- 

 thelium (p. 26). 



Genus Henneguya Thelohan. 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. Nu- 

 merous species. 



H. psorospermica T. (Fig. 216, p). In gills of Esox and Perca; 

 cyst formation; total length of spores 35-40ai. 



H. exilis Kudo (Figs. 211; 216, q-s). 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/i by 4-5^4 wide by 

 3-3.5m thick. 



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

 Micropterus salmoides; spores 13.5-15ai long, 8-9/x wide, 6-7.5)Lt 

 thick; caudal prolongation 30-40/x long. 



Order 2 Actinomyxidia Stole 



The Cnidosporidia placed in this order have been less frequent- 

 ly 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 are plainly visible w vivo. One to several sporo- 

 plasms occur in each spore. In the fully grown stage, the body is 

 covered by a membrane and contains always 8 sporoplasts which 



