136 SIDNEY F. HARMER. 
The Bismarck-brown is deposited only in the granules of 
the funicular tissue. Thus the finer processes of that tissue, 
which are devoid of granules, remain quite colourless after the 
action of the pigment. The nucleus thus becomes visible, in 
most cases, as a clear area, unstained by the Bismarck-brown 
(fig. 18, A). 
6. Bugula avicularia. 
The Bismarck-brown is taken up in intensely brown-red 
granules by the tentacles and by the proventriculus, cecum, 
stomach, and rectum of the functional polypides, the cecum 
being the part which becomes most deeply pigmented. The 
inner borders of the cells of the pharynx become distinctly 
brown ; but the pigment is here diffuse, and not in the form 
of a granular deposit. No pigment is deposited in the ceso- 
phagus (region between pharynx and proventriculus), nor in 
the clear area on the base of the czecum, nor in the intestine. 
These parts may, however, acquire a faint yellow tinge. In 
“brown bodies” which are in process of formation the remains 
of the stomach, &c., take up the pigment, none of which 
is absorbed by the fuily-formed ‘brown bodies,” nor by 
the polypide-buds which do not yet communicate with the 
exterior. 
Most of the funicular tissue remains uncoloured, but in 
some cases groups of intensely brown spherules are observed 
here and there in the body-cavity. This is especially the case 
in the region surrounding a “brown body.” The leucocytes 
become hardly tinged with yellow. 
The Bismarck-brown is taken up freely by young, growing 
cells. The growing-points and the young avicularia hence 
become strongly pigmented. Most of the pigment is deposited 
in these regions in the funicular tissue ; but some of it appears 
to be in the ectoderm, which can also be traced in some of the 
older zoeecia as a series of small cells, separated from one 
another by considerable intervals, and stained brown by the 
action of the pigment. The tactile bodies of the old avicu- 
laria and the surrounding regions also become pigmented. 
