THE INTESTINAL PROTOZOA OF FROGS AND TOADS. 209 
in R. esculenta or Bufo. It is less frequently present than 
Trichomonas. 
Division.—Stages in division are very difficult to find. I 
had examined a very large number of living animals and had 
made over two hundred moist film preparations before I lit 
upon a single stage. When present they usually occur 
together. By making a large number of preparations I have 
been able to find practically every phase of division, though 
my observations on the living organisms have been fragmen- 
tary. I have not succeeded in following out the entire process 
from beginning to end in one and the same animal. 
Division is longitudinal and takes place as follows (see 
Pl. 2, figs. 4-12): The first thing to be seen is that the 
axostyle and nuclear membrane vanish, being apparently 
absorbed, so that a form like that shown in fig. 4 is produced. 
The chromatin lies freely in the neighbourhood of the 
blepharoplast in the form of small granules of varying sizes. 
Even at this stage (fig. 4) it can usually be seen that the 
blepharoplast itself is becoming elongated, assuming a dumb- 
bell shape. It then becomes drawn out to such an extent that 
it takes on the appearance ofa littlerod. Two flagella remain 
at either end of this rodlet? (fig. 5). It appears to me that of 
the two granules which normally make up the blepharoplast 
one bears the posterior flagellum and the other bears the 
three anterior (cf. fig. 4). But during the division of the 
blepharoplast to form the rod one anterior flagellum in some 
way migrates over to the posterior flagellum, so that two 
flagella come to lie at either end of the rod (fig. 5). Next, the 
ends of the rodlet show an enlargement, so that the whole of 
the structure derived from the blepharoplast assumes the 
appearance of a very attenuate dumbbell (fig. 6). At the 
same time the chromatin granules, which were previously 
lying in a small indefinite heap, arrange themselves in the 
1 The origin of the flagella is not always made out with ease. For, 
owing to the way in which they get curled up, superimposed and en- 
tangled, they present appearances which at first sight are frequently 
very deceptive. 
