OBSERVATIONS ON A FLAGELLATE OF GEECOMONAS. 241 



Some Observations on a Flagellate of the Genus 



Cercomonas. 



By 



C. M. Woiiyon, ilI.B., B.S., B.Sc, 



Pi'otozoologist to the London School of Tropical Medicine. 



With 19 Text-figures. 



In tlie present paper I shall describe a flagellate of the 

 genus Cercomonas, a genus first created by Dujardin, in his 

 ' Historie Naturelle des Zoophytes lufusoires,' published in 

 1841. Since Dujavdin's original description numerous flagel- 

 lates have incorrectly been attributed to this genus, so much so 

 that Klebs, in his ' Flagellatenstudien ' (1893), says that this 

 genus has not been defined with sufficient accuracy, that it 

 has been confused with Heteromila and Bodo by the over- 

 looking of the tail flagellum, and that the genus Cercomonas 

 must be rejected. It is undoubtedly true that the genus 

 Cercomonas is very confused, and this confusion has been 

 considerably lieightened by the description of Cercomonas 

 from the intestine of man and other animals. Davaine (1854) 

 was the flrst to record the presence of Cercomonas in the 

 evacuations of a man sufl:'ering from cholera. Without going 

 into the question of the correctness or otherwise of Davaine's 

 conclusions, it is undoubtedly a fact that many observers, 

 noting the presence of active flagellates in the intestinal 

 contents, have attributed them at once to the genus Cerco- 

 monas, and as a result of this various species of Trichomonas, 

 Lamblia, and possibly other flagellates have been included in 

 this genus. In the present instance the flagellate to be 



