430 Col. Sir D. Bruce and others. Trypanosome [May 24, 



Nucleus. — The nucleus is oval in the long and slender and intermediate, 

 and round or oval in the short and stumpy. One peculiarity about the 

 nucleus of this species is that it is frequently placed far back in the body of 

 the organism. This peculiarity is found in the short and stumpy non- 

 flagellar forms (Plate 11, figs. 4 to 11), and more rarely in the intermediate 

 (Plate 11, figs. 12 and 13) ; never in the long and slender. The percentage 

 among the short and stumpy forms is often large, as will be seen by Table V. 

 As the percentage of these non-flagellar forms is 24"8 of the whole, it is easy 

 to calculate the percentage of the posterior nuclear forms to the whole body 

 of this trypanosome. 



Micronucieus. — Small and round, and situated, on an average, 2 microns 

 from the posterior extremity in the long and slender, 1"6 in the intermediate, 

 and 1*4 in the short and stumpy. 



Undulating Membrane. — This, as in T. brucei and T. gambiense, is well 

 developed and thrown into bold folds and undulations. 



Flagellum. — The flagellum in the long and slender averages 5 - 8 microns 

 (maximum 11, minimum 2), and in the intermediate 3 - 3 microns (maximum 9, 

 minimum 1). There is no free flagellum in the short and stumpy forms. In 

 T. brucei the short and stumpy, non-flagellated forms mostly He between 

 13 and 21 microns. This is not so in the trypanosome under consideration, 

 as the following table shows : — 



Table VI. — Number of Flagellated and Non-flagellated Forms found among 

 1220 Trypanosomes of the Human Trypanosome Disease of Nyasaland. 



Length, 



Non- 



Flagel- 



Length, 



Non- 



Flagel- 



Length, 



Non- 



Flagel- 



microns. 



flagellated. 



lated. 



microns. 



flagellated. 



lated. 





flagellated. 





Short and stumpy. 



Intermediate. 



Long and slender. 



14 



1 





22 



5 



60 



25 





91 





4 







2 



64 



26 





107 



16 



19 





24 





93 



27 





110 



17 



42 











28 





104 



18 



62 



1 









29 





87 



19 



74 



7 









30 





49 



20 



56 



19 









31 





27 



21 



37 



54 









32 





23 















33 





13 















34 

 35 

 36 





7 

 1 

 1 





295 



81 





7 



217 









620 



