NATURE OF EXCRETORY PROCESSES IN MARINE POLYZOA. 141 
into two round masses, one situated at the apex of the 
cecum, and the other at the opposite end of the stomach. 
This is exactly what happens in the degeneration of the normal 
alimentary canal.! 
At 238 hours from the first immersion in indigo-carmine 
new polypide-buds were commencing to appear in a good 
many of the zoecia, many of which, at the 264th hour, had 
the appearance shown in PI. II, fig. 1. The degenerating 
tentacles can be distinctly made out, as well as the two masses 
of indigo-carmine (mixed with the normal pigment of the 
stomach, and so of a green colour) derived from the wall of 
the alimentary canal. The leucocytes containing the absorbed 
pigment are grouped in a dense mass round the ‘ brown body,” 
and are enveloped in funicular tissue, strands of which radiate 
out to various parts of the body-wall. Someof these strands 
contain blue leucocytes, intermingled with which were seen, 
in some cases, granules of the brown or orange pigment found 
in the normal zoecia (Pl. III, figs. 23, 24). The funicular 
tissue and the muscles shown in the sketch are perfectly colour- 
less. The whole of the indigo-carmine taken up by the animal 
is contained in the “ brown body”’ and leucocytes. 
One of the strands of funicular tissue passing from the 
“brown body” is thicker than the rest. It is directed towards 
the operculum, and the polypide-bud is attached to it, having 
shifted its original position, and slipped down the strand of 
funicular tissue in the direction of the ‘ brown body.” The 
polypide-bud is pointed at the end turned towards the oper- 
culum, and its walls are here thinner than elsewhere. This 
portion will become the tentacle-sheath of the new polypide. 
Somewhat later (286th hour) many of the polypide-buds had 
developed tentacles. The tentacle-sheath had become very 
thin, and was sharply differentiated from the proximal end of 
the bud. The tentacles were present as a bilateral incomplete 
ring of small tubercles developed on the side of the bud turned 
towards the opercular surface of the zocecium, the ring being 
open on the side nearest the operculum. The intestine and 
1 Haddon, loc. cit., fig. 13 (pl. xxxviii). 
