354 
Crithiclia gerridis 
forms of the parasite. They are from S/x to 1 g long by 2/x to 4</x broad. 
Their ectoplasm is slight and the endoplasm is richly granular. The 
nucleus lies often to one side, and is usually oval (Figs. 1—7). Darker 
staining chromatin granules are preseut in the nucleus. The darkly 
staining blepharoplast is usually rod-shaped (Figs. 1—4) but occasion¬ 
ally appears round (Fig. 13). It is situated near the periphery, often 
away from the nucleus and may lie somewhat transversely to the long 
axis of the pre-flagellate (Figs. 1, 2, 6). Often the outline of the 
blepharoplast is entire, but in forms about to divide, it may show a 
constriction in the middle (Fig. 16). The future flagellum appears 
as an area staining pinkish with Giernsa (Fig. 7) or deeply blue with 
Delafield, lying near the nucleus and the blepharoplast. This area next 
becomes somewhat rod-like and finally grows out as a delicate thread 
(which readily takes up chromatin stains) forming the flagellum 
(Figs. 8—11). The periplast, the somewhat rigid, condensed ectoplasm, 
of the body remains in close contact with the flagellum and becomes 
drawn out with it, forming a fine narrow membrane (Fig. 19). At 
first, the flagellum lies near the edge of the body, in fact usually 
touching it (Figs. 8, 9, 10) but as growth proceeds, it gradually be¬ 
comes free at the distal end (Figs. 11,12,13,14), but the fine membrane 
connects it to the body for at least half its length. 
Longitudinal division (Figs. 16—20) occurs in the pre-flagellate 
forms as well as in those possessing flagella. As the process is much 
the same in both forms, it will be described in dealing with division. 
Tice Flagellate Stage. 
The general structure of the fully developed flagellate has already 
been indicated. 
The long gregariniform body of the Crithidia has a very definite 
outline (Figs. 21—46). It is not rigid, however, but elastic and 
capable of active movements. The periplast is distinct and stains 
somewhat pinkish with Giemsa. The endoplasm is distinctly alveolar 
(Figs. 28, 39, 43), and concentration of protoplasmic granules occurs 
along the strands. 
The undulating membrane (Figs. 34, 41—45) is very definite and 
stains particularly well with gentian violet and thionin. There are 
indications of myonemes (Figs. 41, 42, 44, 45) in some specimens, 
and this is not surprising, seeing that there are similar contractile 
structures in the membranes of Trypanosomes and of Spirochaetes. 
