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HANDBOOK OF PROTOZOOLOGY 



Oikomonas termo (Ehrenberg) (Fig. 53, a, h). About 4 to 

 5 microns long. Stagnant water and soil. 



Genus Histomonas Tyzzer. Parasitic in domestic fowls. 

 Body amoeboid with usually one flagellum which is connected 

 with a blepharoplast. 



Histomonas meleagris (Smith) (Fig. 53, c). Length 12 to 

 15 microns. Supposed to be the cause of the "black-head" of 

 turkeys and chicken. 



Fig. 53 a, b. Oikomonas termo. a, a stained trophozoite (XIOOO after 

 Martin); b, living cyst (X1250 after Sandon). 



c. Histomonas meleagris. X700 (After Tyzzer). 



d. Rhizomastix gracilis. XIOOO (After Mackinnon). 



e. Cryptobia helicis. X 1 900 (After Beiaf). 



f. C. borreli. X650 (After Mavor). 



g. h. C. cyprini. X 665 (After Plehn). 



Genus Rhizomastix Alexeieff. Body rounded with a central 

 nucleus. A blepharoplast is located between the nucleus and 

 the posterior end of the body. A long fiber runs from it to the 

 anterior end and continues into the flagellum. In the spherical 

 cyst, the nucelus undergoes division. 



Rhizomastix gracilis Alexeieflt (Fig. 53, d). Body about 13 

 microns long, flagellum 20 microns long. In the intestine of 

 axolotlesand tipulid larvae. 



Family 5 Cryptobiidae Poche 



Biflagellate trypanosome-like Protomonadida. One fla- 

 gellum free, the other marks the outer margin of an undulating 

 membrane. Blepharoplast is an elongated rod-like structure, 

 often referred to as the parabasal body. All parasitic. 



