Os ae DPT ae, EE RE NTT ET Cc Rg ate 
as Infusoria flagellata. 197 
the slightest possible tremulous vibratory motion. Within a 
_ very few minutes after this, the flagellum began to shorten as 
_. if retracting, reminding one of the running down of a cotton- 
thread in the flame of a candle, and in one minute’s time it be- 
came reduced (fig. 12, 7) to a length which was somewhat less 
than half the height of the collar (4), and then it rapidly dis- 
appeared and left no trace of its former position. During this 
process the body shortened and became broader (fig. 12) in the 
same direction that the plane of the are of the flagellum for- 
merly trended in, and consequently the contractile vesicles (cv) 
were more widely separated; and the front (fr) also having 
become proportionately extended laterally, the base of the col- 
Jar (0) was also increased in diameter until it almost equalled 
_. i the distal end, so that, as a whole, it was almost cylin- 
ical. 
Tn less than fifteen minutes after the preparatory stage was 
_ observed, the collar had become cylindrical (fig. 13,6) by a 
combined action of the base and distal end, which consisted in 
_ a narrowing of the latter and a broadening of the former. 
It was not until 1.15 p.m. that a decided mark of incipient 
self-division became evident in the guise of a narrow, slight 
furrow (fig. 14,¢), which extended, medianly, from the front 
to over halfway toward the posterior end of the body. By this 
time the body had broadened until it was wider than long, and 
the collar (4), having followed this expansion at its basal por- 
tion whilst its upper extreme had.contracted a little, had as- 
sumed the form of a high truncate cone. 7 | 
In two or three minutes after this, the body had become 
_ distinctly indented (fig. 15, ¢!) at the anterior termination of 
the furrow (fig. 15,¢), and the latter had grown longer and 
more distinct, whilst the collar (6) had approximated more 
closely in shape to a perfect cone. 
In another minute or two the anterior indentation (fig. 16, !) 
had become so deep and broad that the body presented a 
cordate outline when seen from its broader aspect, whilst the 
furrow (e) appeared to extend to its base, and the distal end of 
the collar (6) had so nearly closed up as to give that body an 
almost completely conical form, with a slightly collapsed 
periphery. 
From this moment the process of reduction ceased; and soon 
after, the cone-shaped collar began to expand (fig. 17, 6). Con- 
sentaneously with this, the anterior indentation (e!) had be- 
come sharper and deeper, and (with the lateral median furrow 
(ce) of each of the opposing broad flanks of the infusorian act- 
ing in combination with it) had split the body about halfway 
to its base. The most remarkable phenomenon observable at 
