240 



FLAGELLATA CERCOMONAS. 



these contains numerous free-living species, while the latter is wholly 

 parasitic (in both higher and lower animals). The figures above 

 (Fig. 117) represent Cercomonas muscce, a parasite often found in 

 abundance in the chylific stomach of the house-fly, and also (Fig. 119) 

 Trichomonas batracJiorum from the cloaca of the frog. They show 



FIG. 120. Hexamita intestinalis, in the young and adult states. 

 (After Stein.) 



veiy distinctly the differences between the species in question, yet 

 even lately they have been more than once confounded. Along with 

 T. batrachorum, and hardly distinguishable from it with a low power, 

 there very often occurs another parasite, belonging to the genus 

 Hexamita, which I also figure for purposes of comparison (Fig. 120). 



Cercomonas, Dujardin. 



Bodo, Ehrenberg, and others. 



Monadince, with an oval or lonyish body, which is generally nar- 

 rowed posteriorly, and often prolonged into a terminal filament ; while 

 anteriorly it is provided with a long and thin simple flagellum. 



Cercomonas differs from the related genera, Monas and Bodo 

 (sensu stricto), chiefly in the simplicity of its ciliary apparatus. At 

 the base of the flagellum Monas has two short and fine hairs, which 



1 Grasai, loc. cit., pp. 12-22. 



