STUDIES ON CEYLON HAMATOZOA. 675 
On one occasion I observed the whole process under a high 
power in an already pear-shaped individual. The flagellum 
can only be said suddenly to have appeared as a short, 
relatively thick process at the blunt end of the organism. 
This lengthened and became motile, and after a time its 
origin from the body appeared to le more laterally, and a 
sheht ridge became visible at that point. Iam inclined to 
think that the ridge is the first appearance of the undulating 
membrane. 
At this stage again, both as observed on the slide and 
when the process takes place, as will be seen later, in the 
leech, much variation in small detail is to be remarked, espe- 
cially in relation to the relative times at which the different 
processes occur. Thus in the present case the preparation 
for the second division may, and very often does, take place 
before the completion of the first. Or, on the other hand, 
the two products of the first division may become quite 
separate before any preparation for the second division can 
be detected. In the matter of the flagella there is also much 
variation. Sometimes all the four flagella are developed 
before the first division occurs, or this may not take place 
until the completion of the second division. Generally 
speaking, the development of the flagellum lags behind 
when the process occurs on the sealed slide, while in the 
leech the flagella are developed as a rule very early. 
The typical pear shape, which ultimately becomes fusiform, 
may be adopted very early ; in fact, sometimes at the second 
division the protoplasmic body will adopt the form of a 
longitudinally-furrowed cone rounded at the broad end. 
These furrows are rather curious, as there may be a number 
of them giving the animal a ridged appearance. The deepest 
furrow 1s where the ultimate line of division occurs. The 
other furrows disappear. The leneth of the flagellum is 
again in some cases considerable before the body of the 
organism begins to lengthen at all, and rounded little 
creatures, with quite long flagella, may not uncommonly be 
seen in blood from the crop of the leech; they are of quite 
