NATURE OF EXCRETORY PROCESSES IN MARINE POLYZOA. 155 
the wall of the alimentary canal, and probably from the czecum.' 
These vesicles contain granules of Bismarck-brown, and may 
be seen in the stomach, intestine, or rectum, where they are 
no doubt on their way to the exterior. The effect of the con- 
tinuation of this process was that, whereas the alimentary 
canals were brightly coloured with Bismarck-brown shortly 
after their immersion in that fluid, many of the polypides, at 
the 143rd hour, possessed brightly coloured tentacles, whilst 
the alimentary canals had become almost colourless, or at 
least were much less brightly coloured than at an earlier 
period. 
At the 192nd hour the alimentary canals of all those poly- 
pides which were functional at the beginning of the experiment, 
and which had not since degenerated to ‘‘ brown bodies,” had 
got rid of almost every trace of Bismarck-brown, while the 
tentacles still remained brilliantly coloured by that pigment. 
At the 212th hour the alimentary canals of some of these 
polypides with coloured tentacles were quite colourless, and it 
was obvious that the polypides had been obliged to discharge 
all the granules normally contained in the wall of the stomach, 
&c., in order to excrete the Bismarck-brown. The pigment 
taken up by other parts of the colony (growing-points, &c.) 
showed no appreciable diminution in quantity. In those 
zocecia in which the “ brown bodies” were stained, the body- 
cavity contained a considerable quantity of irregular masses 
of granules coloured by Bismarck-brown. This fact further 
supports the view which has been already suggested, that the 
‘brown bodies ” may undergo a certain amount of fragmenta- 
tion in the body-cavity. 
At the 378th hour, polypides with tentacles stained by Bis- 
marck-brown were still left, although the colonies had been 
kept, since their original immersion in Bismarck-brown, in 
pure sea-water. The leucocytes had got rid of nearly all their 
pigment, having probably excreted it into the masses of brown 
granules seen in various parts of the body-cavity. 
1 The vesicles were frequently noticed in the normal animal, and in one 
case in B. neritina. 
