GENUS: TRICHOMONAS 



647 



It must, however, be mentioned that flagellates of the genus Tricho- 

 monas are very liable to exhibit changes of structure, so that they appear 

 to resemble members of another genus. By detachment of the membrane 

 flagellum a flagellate of genus EutricJiomastix is simulated. The genus 

 Hexamastix could be accounted for by supposing that the membrane 

 flagellum of a Trichomonas with five 

 anterior HngeWn (Pentatrichomonas) 

 had become detached from the 

 membrane, so as to give rise to 

 forms with six anterior flagella and 

 no undulating membrane. The 

 axostyle and the supporting fibre of 

 the undulating membrane may be 

 difficult to detect, so that forms 

 with a number of flagella and no 

 other structures result. It has 

 been shown above (p. 310) that 

 the genus Protetramitus was 

 founded on what were merely 

 altered forms of Trichomonas or 

 Eutrichomastix. It is not im- 

 probable that the genus Tricho- 

 mitus was similarly established for 

 flagellates which actually belong 

 to the genus Trichomonas, and in 

 which the axostyle was for some 

 reason invisible, as not infre- 

 quently occurs with undoubted 

 Trichomonas. When such forms 

 are encountered in films, careful 

 search will usually disclose a 

 series connecting them with the 

 typical unaltered Trichomonas. 

 In practically every film of material 

 containing Trichomonas there 

 occur rounded cytoplasmic bodies 

 possessing a nucleus and blepharo- 

 plasts, but with no other struc- 

 tures visible, similar rounded forms in which the flagella can be seen, 

 others with the axostyle evident, and, finally, the typical Trichomonas 

 with the undulating membrane and its attached flagellum. Under these 

 circumstances the determination of genera, which may be regarded 



Fig. 265. — Flagellates from the C^cum 

 OF THE Fowl (x 4,000). (After 

 Martik and Robertson, 1911.) 



A. Ohilomastix galUnarum. 



B. Trichomonas eberthi. 



C. Trichomonas galUnarum. 



D. Eutrichortiastix galUnarum. 



