GENUS: CERCOPLASMA 



371 



of 3-5 to 5 microns. The leptomonas and trypanosome forms are of the 

 usual dim.ensions, being 18 to 20 microns in length, with a flagellum up 

 to twice the length of the body. All intermediate stages between these 

 small forms and the giants occurred. In the rectum, small forms, 4 to 10 

 microns in length, were found. These were evidently encysting forms. 

 It is difficult to account for the giant forms, which have been seen only 

 in this and the allied flagellates, H. mesnili and H. lineata, though smaller 

 forms of the same type occur in Chatton's H. roubaudi described below 

 (Fig. 176). It appears to be not improbable that they are merely abnormal 

 overgrowth forms, in which, for some reason, nuclear division has been 

 delayed, allowing a great increase in the cytoplasm to take place, as occurs 



Fig. 172. — H&rpetomonas mirabilis from Pycnosoma initorium, showing Various 

 Trypanosome, Leptomonas, Elongate Cercoplasma, and Eounded 

 Forms (x 900). (After Roubaud, 1909.) 



in the case of Trypanosoma rotatorium of frogs, Trichomonas vaginalis, 

 and other flagellates. 



Herpetomonas mesnili (Roubaud, 1908) was first called Leptomonas 

 mesnili by Roubaud (19086), and later included in his genus Cercoplasma 

 (1911a). It is a parasite of Lucilia latifrons, and Lucilia sp. of the Congo. 

 Both this parasite and H. mirabilis were later found by Roubaud in a species 

 of Pycnosoma and Lucilia in the French Sudan. In H. mesnili, the giants 

 are not more than 70 microns in length, while the small forms vary from 

 7 to 8 microns and upwards, and have a flagellum from 12 to 14 microns 

 in length. Round and encysting forms are not described. The flagellate 

 was only seen twice in the Congo — once in a fly in pure culture, and 

 once in association with two other flagellates, one morphologically a 

 crithidia and the other a leptomonas. 



