ClilTllWlA ML.'S'JAi:-DOMESTJCA£ 17U 



from the bodies of the organism in making the fihn, some of their 

 figures are not unlike those of Cnthidia gerridis, parasitic in the 

 alimentary tract of an Indian water-bug, Gen-is fossarum Fabr., 

 and described by Patton (1908). 



Rosenbusch (1910) describes this species of Crithidia as being 

 ver}' numerous. The flagellates were found covering considerable 

 patches of the peritrophic membrane of the intestine to which 

 they were attached by their anterior ends. They showed iiTegular 

 flagellate movements. In shape they were flattened laterally, the 

 end of the body gradual h' tapering off to a blunt extremity. The 

 pointed anterior end terminates in the free flagellum. Rosenbusch 

 gives the following as the dimensions of his flagellates : length, 

 8-25 /x; width, 1-2/i; length of flagellum, 12 /i. Post-flagellate 

 stages were also found; these were shortened and rounded and 

 possessed no flagellum. 



It should be pointed out that there is in the minds of a 

 number of those who have studied these flagellates a doubt as to 

 whether these flagellates, which have been described as Cnthidia, 

 are really distinct parasites ; they may be stages in the life-history 

 of Herpetomonas. Patton and Strickland (1908) call attention to 

 the marked resemblance of Werner's parasites to the post-flagellate 

 stages of Herpetomonas muscae-domesticae. In li^'ing specimens 

 Patton has seen the flagellates of the house-fly collecting in masses 

 in the rectum of the insect where the t}"pical long forms shorten, 

 di\ade and eventually round up, and these authors rightly point 

 out that Werner's contention that the difference in size between 

 his parasites {Crithidia) and the flagellates of H. muscae-domesticae 

 is an argument in favour of their being unconnected forms \vill not 

 hold good in view of the marked dissimilarity in form found in 

 the different stages of the life-history of H. m,uscae-domesticae. 

 Dunkerly (I.e.) has described as a distinct flagellate Leptomonas 

 muscae-domesticae, to which I shall refer shortly. Here again a 

 non-specialist of the flagellates Ls in doubt as to its relationship. 

 Further investigation will alone clear up these uncertain and 

 disputed points ; in the meantime I am recording these flagellates 

 under the names and in the manner in which thev have been 

 described. They may be distinct or developmental forms of two 

 species or of only one. 



12-2 



