108 



OTHER FLAGELLATES 



A few phytoflagellates are coprophilic 

 and may be mistaken for true parasites, 

 and still fewer are parasitic. These will 

 be discussed below. 



PARASITIC FLAGELLATES 



The parasitic mode of life has arisen 

 independently a number of times in this 

 group. Free-living species or genera in 

 distantly related or unrelated families 

 have found suitable living conditions in 

 various hosts. Many of these were pre- 

 viously inhabitants of stagnant water. 

 The fact that so few of them are pathogenic 

 effectively refutes the notion that para- 

 sites tend to be pathogenic in their first 

 association with a new host and that later 

 on the host and parasite adjust to each 

 other, the latter becoming less pathogenic 

 and eventually commensal. 



FAMILY MONOCERCOMONADIDAE 



This family, like the Trichomonadidae, 

 belongs to the order Trichomonadorida. 

 Its members have either a free or adherent 

 trailing flagellum, but lack the undulating 

 membrane and costa found in the Trichom- 

 onadidae. Four genera, Monocercomonas , 

 Hexamastix, Protrichomonas and Cliilo- 

 mitus, occur in the intestinal tracts of 

 domestic animals. 



Genus MONOCERCOMONAS Grassi, 1879 



In this genus the body is piriform, 

 with a rounded anterior end. There is a 

 pelta. The cytostome and nucleus are 

 anterior. There are 3 anterior flagella 

 and a trailing one. The axostyle projects 

 beyond the posterior end of the body. 

 Travis (1932) showed that Trichomastix 

 Blochmann, 1884 and Entrichomastix 

 Kofoid and Swezy, 1915 are synonyms of 

 Monocercomonas . Morgan (1944) gave a 

 checklist of species of the genus; it in- 

 cluded 20 species, of which 4 were from 

 mammals, 4 from birds, 2 from reptiles, 

 1 from amphibia, 2 from fish and 7 from 

 insects and other arthropods. Others 

 have been described since. 



Fig. 13. Monocercomonas. 

 (Original) 



X 2800. 



Monocercomonas ruminantium 

 (Braune, 1914) nov. comb, occurs in the 

 rumen of cattle. In addition, Morgan and 

 Noland (1943) found what was probably the 

 same organism in material from the sheath 

 of bulls. 



The body is about S/i long, with 3 an- 

 terior flagella about 8)i long and a trailing 

 flagellum a little longer. The axostyle is 

 curved and does not extend beyond the 

 body, altho the posterior end is pointed. 

 A line of granules runs beside the convex 

 side of the axostyle. This species is non- 

 pathogenic, but must be distinguished from 

 Tri trichomonas foetus. 



Synonyms of this species are Tri- 

 chomonas noiiiiiaiitiiiiii Braune, 1914; 

 Tricercomitus ni)>iiiiaiitiii»i (Braune, 1914) 

 Christl, 1954; and Tritrichomonas rumin- 

 antium (Braune, 1914); but not Tricho- 

 ))iastix ruminantium Braune, 1914. Altho 

 Braune (1914) assigned this species to the 

 genus Trichonioiias and succeeding work- 

 ers have followed him in this or at the 

 most have changed the generic name of 

 Tritrichonionas. Christl (1954) pointed out 

 that the absence of an undulating membrane 

 made this assignment incorrect. Christl 

 transferred it to the genus Tricercomitus, 

 but it belongs more properly to the genus 

 Monocercomonas . 



