736 



THE ANIMAL PARASITES OF MAN 



three forwardly directed flagella and a fourth backwardly directed one 

 in the cytostome, which is well developed (fig. 423). Some authors 

 consider that the fourth flagellum forms the edge of an undulating 

 membrane in the cytostome. 



Diagrams of Chilomastix mesnili are given in fig. 423. 



FIG. 423. Chilomastix ( letramitus] mesnili. a, b, c, flagellate forms ; 

 d, rounded or encysted form. X 2,500. (Original.) 



Giardia (Lamblia) intestinalis (see p. 57). Alexeieff 1 (1914) con- 

 siders that Lamblia intestinalis, Lambl, should be placed in the genus 

 Giardia, Kunstler, 1882. Bipartition occurs in the encysted state. 

 The axostyles persist in the quadrinucleate cyst. 



Cercomonas hominis (see p. 61). This parasite is considered by 

 some authors to be of a doubtful nature, as it is thought to have been 

 mistaken for deformed or incompletely observed Trichomonas or Chilo- 

 mastix or even Lamblia. 



Wenyon 2 (1910) described Cercomonas longicauda from cultures 

 of human faeces. It is considered that the genus is very confused, 

 and the author points out that the tail flagellum has been overlooked. 

 He considers that the genus Cercomonas should include flagellates 

 with an anterior blunt end from which arises a single long flagellum, 

 and a posterior tapering end also with a flagellum, which can be traced 



1 Zool. Anzeiger, xliv, p. 210. 



- Quart. Journ. Micros. Set., Iv, p. 241. 



