88 Cc. CLIFFORD DOBELL. 
7th day. Monads plentiful, many dividing and a con- 
siderable number conjugating. 
Sth ,, Many monads conjugating, some encysting and 
some dividing. 
Oc haere 
10th ,, | Conjugation practically finished; a few dividing; 
JUNAn encystment. 
12the ey 
? 
? 
&e. 
Sometimes the life-cycle extends over about seven days ; 
at other times it may take more than twice as long. 
(1) Asexual multiplication. 
This takes place by means of longitudinal division, and 
may easily be observed in the living animal. As a rule 
division is proceeding most actively in cultures about a week 
old. By fixing and staining film preparations at this time a 
large number of specimens showing all stages of division may 
be obtained with considerable ease. 
General account of division (see Pl. 4, figs. 1-10).— 
The monads grow toa large size before division. The first 
sion of the onset of the process is observable in the locomotor 
apparatus. It is seen that the animal (PI. 4, fig. 1), which was 
actively swimming about, is becoming sluggish in its move- 
ments. . After a short time it comes to rest completely, and 
the flagellum displays slow coiling movements (fig. 2). 
Gradually the movements become slower and slower, and 
at the same time the flagellum gets shorter and shorter, and 
is finally completely drawn in (fig. 3). During this process 
the nucleus has elongated, and now appears as a bright band 
stretching across the cell. After watching the motionless 
monad for a few minutes the observer will see two minute 
peg-like outgrowths appearing at the anterior end. These 
are the new flagella, which grow up side by side, and very 
