HOST-PARASITE RELATIONS: INTESTINAL PROTOZOA 



anterior end which she suggests may be a cytostome. 

 A similar clear area is noted by Hinshaw ( 1926b). Ohira 

 and Noguchi (191 7) observed binary longitudinal fission 

 and multiple fission of this species in cultures, and Hin- 

 shaw (1926b) has described both nuclear division and 

 cell division. No other stages in the life-cycle have been 

 found. 



3. TRICHOMONAS HOMINIS (Fig. 9) 



The trichomonads of the human intestine are very 

 difficult to prepare for microscopic study and their 

 morphology, therefore, has not been worked out in as 

 great detail as that of the other types. The size varies 

 greatly, from Sn to i5At in length by 3^1 to S/x in breadth. 

 The flagella appear to arise from two or more blepharo- 

 plasts near the anterior end. The undulating membrane 

 extends almost the entire length of the body and its 

 flagellum projects out freely at the posterior end for a 

 considerable distance. The axostyle is a clear rod of con- 

 siderable thickness, part of which protrudes from the 

 posterior end of the body. On the other side opposite the 

 nucleus at the anterior end is a well defined cytostome. 

 At the base of the undulating membrane is a heavy, 

 deeply-staining chromatic basal rod. This rod is consid- 

 ered by Kofoid and his students to be a parabasal body, 

 but Cutler (1919a) in Ditrichomonas termitis from 

 termites, Wenrich (1921) in Tritrichomonas muris from 

 rats and Andrews (1925) in Trichomonas termopsidis 

 find another body, which appears when specimens are 

 fixed with osmic or chromic acid, which is apparently 

 the parabasal body. The fact that one of Kofoid's stu- 



132 



