TRYPANOSOMES IN TSETSE-FLIES AND OTHER DIPTERA. 193 
of the parent flagellum. In another species the amount of 
splitting might be much less, or might not extend beyond the 
division of the blepharoplast. I do not wish, at present at 
least, to extend my statements as to the splitting of the 
flagellum beyond the case which I have studied. ‘That the 
flagellum does actually split in T. grayi is shown, I think, 
by the fact that in the early stages the daughter flagellum is 
distinctly finer and more delicate than the parent flagellum 
(figs. 205-208). I see no reason why this should be so if 
the daughter flagellum grew out independently from the 
blepharoplast. 
The process of division described in the foregoing para- 
graphs is that most usually found, and represents, I believe, 
the normal course of events. The commonest departure from 
this course is seen in the division of the flagellum, which may 
be hastened and be completed before the division of the 
nucleus (fig. 213), or even before that of the kinetonucleus 
(fig. 215). This variation shows clearly that the flagellum 
is independent of the kinetonucleus, a fact which, in my 
opinion, is a further indication that the kinetonucleus should 
not be confounded with a true blepharoplast or centrosome. 
' (2) The slender type (figs. 144, 145, 172, 224-226, etce.), 
is very uniform in its characters and exhibits but slight 
variation in contrast with the many forms which I have 
grouped together as the “ordinary” type. The body is 
elongated and slender; the cytoplasm is free from coarse 
granules as a rule, but occasionally a few are seen in the 
posterior part of the body; N is compact, sometimes very 
compressed ; 7 is large, rod-shaped or round, generally filling 
up the whole width of the body, and invariably in front of N; 
the flagellum is distinct and stains deeply ; it stands off but 
little from the body, forming a very shallow undulating 
membrane, which is scarcely or not at all pleated, and the 
free flagellum is very long, and often appears distinctly 
thickened at its free termination. 
The chief variation exhibited by this type is seen in the 
degree of slenderness of the body; usually slender, with a 
