312 HANDBOOK OF PROTOZOOLOGY 



Agarella gracilis Dunkerly (Fig. 133, c). In the testis of 

 South American lung-fish, Lepidosiren paradoxa. 



Family 4 Myxobolidae Thelohan 



Genus Myxobolus Butschli. The spore ovoidal or ellipsoidal, 

 flattened. One or two polar capsules at the anterior end. The 

 sporoplasm contains an iodinophilous vacuole. Rarely with a 

 posterior prolongation of the shell. Exclusively histozoic para- 

 sites in freshwater fishes and amphibians. Numerous species. 



Myxobolus notatus Mavor (Fig. 129, h; 133, d). In the sub- 

 dermal connective tissue of the blunt-nosed minnow, Pimephales 

 notatus, and of Leuciscus rutilus. The tumor enclosing a tropho- 

 zoite reaches a diameter of 7 mm. With a single polar capsule. 

 Fresh spore 17 to 18 microns by 7.5 to 10 microns. The host 

 tissue around the parasite becomes so highly changed that it 

 appears as an epithelium. 



Myxobolus pfeifferi Thelohan (Fig. 133, e-g). In the muscle 

 and connective tissue of the body and various organs of Barbus 

 barbies, B. fluviatilis, and B. plebejus. The tumor containing the 

 parasites reaches a diameter of 7 cm. Most of the infected fish 

 die from the effect (Keysselitz). The spore measures 12 to 12.5 

 microns long by 10 to 10.5 microns broad. 



Myxobolus orbiculatus Kudo (Fig. 133, h, i). In the muscle 

 of the minnow, Notropis gilberti. The preserved unstained spore 

 measures 9 to 10 microns in diameter and 6.5 to 7 microns in 

 thickness. 



Myxobolus conspicuus Kudo (Fig. 133, _;')• In the corium of 

 the head of the short-headed red-horse, Moxostoma breviceps. 

 The trophozoites form tumors or cysts varying in diameter from 

 one-half to 4 mm. (Fig. 129, a). The preserved spore measures 9 

 to 11.5 microns long by 6.5 to 8 microns broad. 



Genus Henneguya Thelohan. The spore circular or ovoidal 

 in front view; flattened. Two polar capsules at the anterior 

 end. Each shell-valve is prolonged posteriorly into a long pro- 

 cess. The sporoplasm contains an iodinophilous vacuole. Most- 

 ly histozoic (some coelozoic) parasites in freshwater fishes. Nu- 

 merous species. 



Henneguya psorospermica Thelohan (Fig. 133, ^). In the 



