OBSERVATIONS ON A FLAGELLATE OF CERCOMONAS. 253 



karyosome (fig. 11). Prowazek describes for Car co- 

 rn on as longicaudia a " ein Art uudeutlichen Zwischen- 

 fibrille/' which connects the karyosome to the insertion of 

 the flag'ella. Prowazek figfures this^ connection as a dark line 

 running from the karyosome to the apex of the nucleus, but 

 I have not been able to detect any structure as definite as the 

 one he figures. 



This flagellate is a very excellent illustration of the fallacy 

 of relying for detail on the old. dry Romanowsky methods of 



Text-fig. 11. 



II. 



Shows connection of karyosome and rliizoplast. 



staining. The nucleus of this organism is clearly visible in 

 the living condition. Thei-e is a definite nuclear membrane. 

 At the centre of the nucleus is a large refractile karyosome, 

 while the space between this body and the nuclear membrane 

 is free from granules. The nuclear membt-ane is drawn out 

 at one point towards the insertion of the flagella. Now if a 

 film of the material containing this flagellate is allowed to 

 dry as in the usual method for the pi'eparation of blood for 

 staining trypanosomes, and stained by one of the modifications 

 of the Romanowsky method, the result may be very beautiful 

 from the colour point of view, but totally misleading in the 

 structure of the nucleus. This latter organ appears in these 



VOL. 55, PAKf 2. NEW SERIES. 17 



