242 C. M. WENYON. 



described was found in the faeces of a patient in the Albert 

 Dock Hospital at the London School of Tropical Medicine. 

 This patient was infected with Entamoeba coli, and in order 

 to observe changes in the encysted forms of this amoeba some 

 of the fajces were placed in a clean glass-stoppered bottle. 

 In the course of a few days it was noticed that large numbers 

 of Hagellates were ])resent. It is probable they had developed 

 from cysts which must have been present in the faces. On 

 first examination it was seen that these flagellates corre- 

 sponded very closely with the original description of Dujardin 

 for the genus Cercomonas. and for this 1 took them to be. 

 On more careful examination I found that the tapering 

 posterior end was in reality a second flagellum, and that this 

 could be traced along the surface of the body to which it was 

 attached as far as the insertion of the long anterior flagellum. 

 The presence of this posterior fliigellum and its attuchmtnt 

 to the body required very careful observation to make out, 

 for it can only be clearly seen in certain portions of the 

 animal, and it is quite conceivable, as Klebs maintains, that 

 Dujardin overlooked this posterior flagelUun. Dujardin's 

 original description of the genus is as follows : 



^' Genre Cercomonas. 



''An. arrondi ou discoide, tuberculeux, avec un prolonge- 

 ment posterieur variable, en forme de queue, plus ou moins 

 long, plus ou moins filiforme. 



Les Cercomonas ne different absolument des jMouads que 

 par uu prolongement posterieur, forme par la substance 

 meme du corps qui s'agglutine au porte-objet, et s'etire plus 

 ou moins, de maniere a n'etre tantot qu'un tubercule aminci, 

 tantot une queue allongee transparente, tantot enfin un tila- 

 meut presque aussi fin que le filament anterieui-, et suscep- 

 tible d'un mouvement ondnlntoire; mais bien scuvent j'ai cru 

 voir les Monades passer par degres I'etat de Cercomonas." 



A comparison of this description with that now to be given 

 will show how closely the two agree. 



The occurrence of this flagellate has been described above. 

 By transplanting into other media I have been able to keep 



