NATURE OF EXCRETORY PROOESSES IN MARINE POLYZOA, 146 
more dense than in the specimens figured on Plate IT; 
and other instances were noticed in which indigo-carmine 
had almost certainly passed from these leucocytes into the 
periphery of the “brown body.” I at first expected to find 
that the leucocytes which had taken up indigo-carmine would, 
in some manner or other, discharge their pigment into the 
“brown body,” with which it would be removed from the 
zocecium through the agency of the young polypide. My ex- 
periments were, unfortunately, incomplete when I had to leave 
Naples, so that I cannot speak with any certainty on this 
point. Iam inclined to believe that the greater part of the 
indigo-carmine taken up by the leucocytes is deposited, in an 
insoluble form, in masses situated in various parts of the 
zocecium (as shown by fig. 9 and, to a less extent, by fig. 5), 
but that some may pass into the “brown body,” as indicated 
in fig. 9, and so leave the zoccium. The unusually dark 
colour of the ‘‘ brown bodies” in the individuals of the colony 
treated with indigo-carmine was possibly due to an admixture 
of indigo-carmine derived from the leucocytes with the normal 
red pigment of the “ brown body.” 
It has already been pointed out that indigo-carmine is freely 
taken up by the ‘lateral cords.” During the formation of the 
“brown body” these cords shrivel, still containing the pig- 
ment, and sometimes becoming divided into two or more 
pieces (fig. 8). The fragments which are left at the distal end 
of the zoecium appear to deposit their pigment as a densely 
blue mass on some part of the inner surface of the wall of the 
zoecium. Other parts of the lateral cords may become 
closely connected with the “brown body,” with which they 
may, perhaps, ultimately pass to the exterior. 
The colony on which these observations were principally 
made did not belong to the experiment previously described. 
Very little indigo-carmine had been taken up, and nearly all 
of it was in the lateral cords and in the granules of the ali- 
mentary canal ; very few of the leucocytes having taken up any 
blue colour. 
I am very much indebted to my friend Mr, A. H. L. New- 
VOL. XXXIII, PART I.—NEW SER. K 
