323 
The leaf-like form seems to gradually change to the second variety 
of T. loricatum described by Franca and Athias. 2 The change is 
brought about by a shortening of the anterior part of the body and a 
complete unfolding of its posterior portion. Forms representing this 
transformation are seen in Plate XXVII, figs. 30 and 31. This 
completes the cycle from T. loricatum to T. loricatum .* 
The first part of this cycle, from T. loricatum to the herpetomonas- 
like forms, was actually observed in a single living parasite which was 
kept under observation during three days. The second part of the 
cyde, from the herpetomonas-like forms back to T. loricatum is 
largely based upon the examination of stained preparations of fresh 
and “kept" blood. We are fully aware of the necessity for caution 
in determining a developmental process from stained specimens. In 
the present instance the deductions we have made from our 
examination of stained preparations have been frequently confirmed, 
and even supplemented by isolated observations on fresh specimens. 
Our statement is supported by the observation of Bouet 0 who saw 
every intermediate stage between rounded forms and adult 
trypanosomes of the T. rotatorium type 2 in his cultures. 
We describe several types of trypanosomes which are constantly 
seen. All are simply developmental variations of T. loricatum. 
I. —Forms resembling the trypanosome found in Hyla arbor ea. 
(a) A short variety (probably identical with T. rotatorium ) 
(b) A long variety. 
(c) A wide variety. 
II. —A lanceolate form resembling somewhat a type described by 
Laveran and Mesnil. 3 
HI.— Forms resembling T. mega * 
(а) T. mega. 
( б ) A coarsely reticulated form. 
(r) A form with large red granules in it. 
IV. — Forms resembling 1 . karyozcukton. 
V.—An unplaced trypanosome. 
, H'.aule (2) evidently saw a considerable part of this cycle, since he believed 
'hat the trypanosomes were produced from the white blood c ° r P^ c J® s ; flage llum 
'hat he hail seen leucocytes each develop an undulating 
He also describes trypa'nosomes which cast off their motileapparatus1 and sc> ag 
became leucocytes. ' The way in which such a mistake could arise is e y P e 
A clump of rounded parasites at the fourth or fifth division bears a very close 
resemblance to a group of white cells. 
