205 
metazoan gametes. For this reason and others, to which we shall 
refer subsequently, we regard it as extremely misleading to name the 
end-bead a blepharoplast, and the extra-nuclear centrosome, a kineto- 
nudeus, for the end-bead (blepharoplast) does not present the 
relationships of a centrosome, or blepharoplast; while the extra- 
nuclear centrosome (kineto-nucleus) does so. Moreover, the extra- 
nuclear centrosome does not, so far as we are aware, present anything 
in common with a nucleus, except its capacity to divide, and in this 
connection such a capacity amounts to nothing, for the capacity to 
divide is one which is, of course, shared by every known centrosome. 
The extra-nuclear centrosome is generally in the form of a thick rod, 
often slightly curved, and sometimes presenting the appearance of 
being divided in the middle. The division of the blepharoplast does 
not appear, however, to take place through any transverse separation, 
which such appearances might suggest. 
The nucleus in T. lewisi lies relatively very near the end of the 
body from which the flagellum projects. In consists of an outer less 
stainable area, and a large inner much more darkly staining globe, the 
intra-mclcar centrosome (karyosome nucleolus). The outer portion 
of the nucleus is often very distinctly bounded, and in such phases of 
the development as those represented in figs. 14-19 might certainly 
be said to possess a membrane. During the phase of the development 
we are now considering, the cells do not present any very definite 
granules in the cytoplasm, which is seen, both under examination 
tloring life with a dark ground illumination, and after proper fixation, 
to consist of a fine protoplasmic foam bounded on the outside by a 
denser and homogeneous layer. 
Having thus briefly described the features of T. lewisi when in 
such a stage as that represented in fig. i, it will be most 
convenient in proceeding to describe the passage of such forms 
^ugh the phases of the cycle we have already outlined, and to 
consider the various divisional and other phenomena as tliey occur m 
relation to this cycle. The form of trypanosome represented m 
% I passes by simple growth into the large forms represented m 
figs. IMS, and all the intermediate stages can be readily foun 
stretching from the morphological condition represented in hg- i 
to that represented in fig. 1;. Among such trypanosomes as those 
represented in figs. 8-1/, two stages of metamorphosis are foun to 
