194 E. A. MINCHIN. 
compressed nucleus (figs. 225, 226), it is sometimes stouter, 
with a round or oval nucleus, thus showing an approach to 
the ordinary young forms (fig. 224, etc.). In one instance 
(Nov. 10th, Ist fly, p.241) [have found such moderately slender 
forms connected by transitions with round forms (figs. 132- 
137). Only in a single instance have I found what appears 
to be division ; but I am by no means certain that this is not 
really a case of two trypanosomes accidentally superposed 
(fig. 147). 
The slender type is distinguished in life by its extreme 
motility. The trypanosomes are seen darting across the field 
of the microscope in the manner aptly termed “en fléche” 
by French writers. The body is held stiff and moves with 
the flagellum, vibrating rapidly in advance. These are the 
forms termed by Novy (82) and by Gray and myself (29) 
“male” forms; I shall consider the point more in detail 
presently. 
As a special development of the slender type should be 
reckoned, perhaps, the immensely elongated forms seen in 
figs. 242-244. Unfortunately I have not noted the region 
in which they occur. A similar form has been figured by 
Gray (P. R.S., 3 78, Pl. XIII, fig. 35). My first impression of 
these remarkable forms was that they were simply sperma- 
tozoa of the fly, but they are connected by transitions with. 
more ordinary forms. 
(3) The Herpetomonas-type is to be regarded as a 
special modification of the slender type, though probably 
originating directly, in some cases, from ordinary young forms. 
The H-forms (as I may term them for brevity’s sake) are 
minute and very slender, with the chief bulk of the body 
behind the kinetonucleus, in front of which the body tapers 
rapidly to a filamentous prolongation, sometimes of consider- 
able length (figs. 163, 164, 169, 170, 184, 185, 187, 188, etc.). 
Posteriorly the body is usually bluntly pointed. ‘The nucleus 
has the form of a clump of granules about the middle of the 
body. The kinetonucleus is invariably in front of the nucleus. 
The cytoplasm is clear, but sometimes contains a few coarse 
