VARIETIES OF TRICHOMONAS HOMINIS 



655 



Chatterjee (1915), and the three-flagellate type Tritrichomonas by Kofoid 

 (1920). It seems doubtful if these forms should be placed in different 

 genera. The type species of Trichomonas is T. vaginalis Donne (1837), and 

 this form has always been seen to possess four flagella, though it cannot be 

 affirmed that the three or five flagellate types never occur in the vagina. 

 Trichomonas hominis, therefore, would be the correct name for the intestinal 

 form with four flagella, there being no need to employ the generic title 

 Tetratrichomonas. The generic names Tritrichomonas and Pentatrichomonas 

 can be employed for the types with three and five flagella, or what appears 

 to be safer is to regard the various types as varieties of one species, so 

 that it is possible to distinguish in the human intestine T. hominis var. 



Fig. 268. — Trichomonas trijpanoides from Intestine of a Termite, Eeticiilitermes 

 Jucifugus, SHOWING One, Two, and Four Anterior Flagella (x ca. 2,500). 

 (After Duboscq and Grasse, 1924.) 



tritricJiomonas, T. hominis var. tetratrichomonas, T. hominis var. j)enta- 

 trichomonas. Duboscq and Grasse (1924) have shown that in the case of 

 T. trypanoides, described by them from termites, there is a single thick 

 anterior flagellum which frequently becomes divided longitudinally to 

 give rise to two, three, or four separate flagella (Fig. 268). The jcommonest 

 type in man is undoubtedly the one with four flagella. Most observers, 

 however, fail to record the number of flagella, which, moreover, are very 

 difficult to count. In an infection in which a certain number of flagellates 

 have, say, four flagella, it will be found that others have a smaller number, 

 so that to determine the prevailing type in any infection it is necessary to 

 count the flagella on a number of flagellates, a procedure which involves 



