226 
Herpetomonas luciliae ii. sp. 
halves of the rhizoplast (PI. VIII, fig. .5). Usually the blepharoplast 
shows no signs of division, but forms may occur in which it has divided, 
although there are no signs of division elsewhere. 
Other forms may be seen with two chromatin filaments in the 
flagellum, as described above, but with no signs of division in the 
rhizoplast. (PI. VIII, figs. 3-6.) 
II. The parasite in the midgut and small intestine. 
The parasites found in this region of the gut are quite distinct from 
those seen in the ‘crop,’ and intermediate forms are difficult to find. 
Both in living and stained specimens, they are seen to be in a state 
of very active division, so that a portion of the gut sometimes contains 
literally myriads of them. 
In the living state, the form of the parasite is seen to be very 
variable, but often it is like a greatly elongate cone with the flagellum 
at the base of the cone. The flagellum is long and wavy. The body of 
the cell measures 15 to 20 ^ x 3 /i; the flagellum is 25 to 40 long. 
Dividing cells are broader. 
The following structural details are observable in stained specimens : 
(a) The cell protoplasm is finely alveolar and stains bright-blue, 
there being no differentiation into periplast and endoplasm. It contains 
the nucleus, blepharoplast, rhizoplast, and chromidia ; and forms a fine 
membrane about the chromatin of the flagellum. In dividing cells the 
protoplasm has a coarser structure. 
(Z>) The nucleus is spherical and situated in the centre of the cell. 
It consists of a reticulate achromatinic matrix, staining pale-pink, in 
which lies a network of chromatin, thickened at the nodes of the 
reticulum. The following stages in the structure of the dividing nucleus 
may be observed : 
(i) The nucleus consists of the achromatinic matrix without the 
finer parts of the chromatin network, so that the latter appears coarser 
and the nodal points thicker. (Fig. 2 h.) 
(ii) The nucleus has an oval form, and lies across the cell; the 
chromatin granules are aggregated around the periphery of the nucleus, 
and also in a transverse line across its longest diameter. (Fig. 2 d.) 
(iii) The nucleus shows chromatin granules which have become 
flattened out, forming a peripheral ring of chromatin, and a transverse 
band lying nearly across the nucleus, but not touching the peripheral 
ring. (Fig. 2/ 
