168 
SYDNEY .1. HICKSON AND J. T. WADSWORTH. 
It was slightly oval iu outline, the two diameters being 
55’5 /ii by 518 /i. A preserved and stained gemmula of this 
stage is shown in tig. 18. At 1.30 the tentacles had con- 
siderably increased in number and in length on one quadrant 
of the gemmula, but had diminished in number over the rest 
of its surface. At 2.10 the main body of the gemmula had 
increased to 62 p in diameter, but on one side a short arm 
process (7'2 ,u), supporting a great many tentacles, had been 
protruded. There was only one tentacle left on the main body. 
Six contractile vacuoles were observed at this stage, and the 
meganucleus was visible and had an amoeboid form with two 
short, thick, pseudopodia-like processes. At 3.10 the arm 
was 25'9 /i in length and the tentacles confined to its distal 
extremity. For the first time a single contractile vacuole 
w’as seen at the base of the arm. At 3.55 the arm had 
increased to 33'3 in length, and a new arm at right angles 
to it was beginning to be formed. At 4.40 the main body 
was losing its circular outline. The new arm, about 14‘8 ju iu 
length, exhibited tentacles, and the first formed arm was 
48T in length. Three inicronuclei were clearly visible at 
this stage in the clear protoplasm. The meganucleus had four 
branches, one directed towards the longer arm, but not extend- 
ing into it, one towards the shorter arm. Another specimen of 
a Fendrosoma, which was probably of the same age as this 
one, was found in a whole mount preparation and is shown in 
hg. 21. The meganucleus is in two parts, but the general 
form of it, apart from this peculiarity, is very characteristic 
of young Deudrosomas of this stage. In this particular speci- 
men there were four well-developed micronuclei. 
The other case of the development of a young Fendrosoma 
from a free-swimming gemmula is illustrated by the figures 
2-7. The ciliated gemmule, at the time it settled down, had 
from eight to twelve contractile vacuoles. The meganucleus 
could be clearly seen, as it was quite colourless as compared 
with the pale yellow tint of the surrounding cytoplasm. It 
was distinctly amceboid, constantly, but slowly, changing 
its shape (fig. 2). Before the cilia disappeared numerous 
