120 INTESTINAL FLAGELLATES AND CILIATES 



be a modified parabasal body; in some forms it is broken up into 

 a row of chromatinic granules. At the point of insertion of the 

 flagella, and serving as the center of the neuromotor apparatus is 

 a basal granule or blepharoplast. Arising near the anterior end 

 and running through the body is a sort of supporting rod called the 

 " axostyle," which, according to Kofoid and Swezy, is also used 

 as an organ of locomotion. At the anterior end at one side of 

 the point where the flagella originate is a slight depression or 

 " cytostome " which serves as a mouth. The small round nu 

 cleus lies in the body just behind the origin of the flagella. 



Trichomonas swims by active lashing movements of the free 

 flagella and by wave motions of the undulating membrane. 

 The body revolves as the animal wends its way through the 

 semi-liquid substances in which it lives. Multiplication is by 

 longitudinal division of the body, the flagella and undulating 

 membranes and internal structures all being duplicated before 

 the animal splits into two. A process of multiple fission resulting 

 in the formation of eight individuals has also been described. 



Encystment, such as occurs in other intestinal protozoans, 

 has definitely been observed only recently in Trichomonas. 

 Some of the flagellates, after escaping from the body with the 

 faeces, soon degenerate, gradually losing all their appendages 

 except the undulating membrane. With- 

 out their flagella, and with their ameboid 

 movements, these animals closely resemble 

 amebse but can usually be identified by the 

 undulating movement which persists at one 

 B side of the body. Others, without losing 

 their appendages, become round and mo- 

 ment stage; B, encysted tionless as if in a cyst, but with no cyst 

 LyTch.) > * (After wall around them. When warmed up 

 they stretch themselves out and resume 



an active life. It is probable that these forms are preparing for 

 encystment, since they correspond with pre-encystment forms 

 (Fig. 31 A) recently described by Lynch. Lynch, who found con- 

 siderable numbers of cysts in a heavily infected case in South 

 Carolina, describes the cysts (Fig. 31B) as thin-shelled, pear- 

 shaped bodies, about three-fourths the size of the active flagellates. 

 The oval body of the animal with its appendages can be seen 

 clearly through the cyst wall in properly prepared microscopic 



