134 SIDNEY F. HARMER. 
the whole of the cecum of old polypides consequently appear 
deep blue-green. In younger (functional) polypides, which 
are normally but slightly pigmented, the blue colour of the 
indigo-carmine is more obvious. 
B. CARMINATE OF AMMONIA. 
The colonies were placed for about two days in sea-water 
containing this substance in solution, and were then trans- 
ferred to a tank containing ordinary sea-water. 
a. Bugula neritina. 
The pigment is taken up by the granules contained in the 
walls of the alimentary canal of those polypides only which 
have actually swallowed solid (precipitated) carmine particles.’ 
The pigment is most copiously deposited in the blind end of 
the cecum, gradually shading off thence on to the rest of the 
stomach. The wall of the rectum and the inner borders of 
the cells of the pharynx also contain carmine deposits. The 
clear patch on the cecum never contains the pigment. 
In some of the zocecia carmine is taken up in granules by 
cells belonging to the funicular tissue. These cells are distinct 
both from the network of pigmented cells and from the leuco- 
cytes, and belong to the type shown for the next species in 
fig. 22. The growing-points are usually brightly coloured 
with red pigment. 
6. Bugula avicularia. 
The pigment is taken up by the same parts of the alimentary 
canal and of the funicular tissue as in B. neritina, being 
most copiously present in the latter position in the growing- 
points. The leucocytes contain no trace of the pigment. 
About twelve days after the commencement of the experiment 
it was noticed that the tips of many of the branches were 
1 C. Vogt (“Sur le Loxosome des Phascolosomes,” ‘ Arch. de Zool. Exp. et 
Gén.,’ v, 1876, p. 320) has shown that carmine given as food is deposited in 
the yellow “hepatic cells ”’ of the stomach of Loxosoma phascolosoma- 
tum, but in no other part of the alimentary canal. 
