204 Herpetomonas aspongopi 
round, or pear-shaped bodies (Fig. 2, a ) measuring from 1 to 2 p in length. 
Their protoplasm stains blue and in parts is very finely vacuolated. 
These round bodies contain two large nuclei somewhat diffuse in 
structure. Nearly the whole of the cell is taken up by the nuclei. A 
general enlargement of this resting body is the first stage towards 
further development. The two large nuclei divide thus forming four 
nuclei (Fig. 2, b and c). Immediately after this the cell divides by 
Fig. 2. All the drawings were made with a camera lucida. 
Magnification : J^-th oil immersion and 4 eyepiece (Zeiss) x 940. 
a Resting stage. 
b and c Division of resting stage showing four nuclei. 
d, e and / Young form somewhat resembling a Leishman-Donovan body. 
g and h Two young forms with flagella. 
i and j Two young forms showing division of blepharoplast and flagella. 
k Young form with blepharoplast and macronucleus divided. 
I, vi and n Adult flagellates. 
o and p Long thin form of adult flagellate. 
q Dividing form with macronucleus divided. 
r and s Dividing forms with macronucleus, blepharoplast and flagellum divided. 
t and u Last stages of division. 
transverse fission. In this last stage one of the nuclei decreases in size 
and probably becomes the blepharoplast of the young immature parasite 
(Fig. 2, d, e and f). I have constantly found these bodies present in my 
preparations and believe that they are the resting stage of Herpetomonas 
aspongopi, but as they were only found in the faeces on two occasions it 
