130 SIDNEY F. HARMER. 
most numerous near the growing edges. On the formation of 
a brown body they are collected into much larger masses, 
which occur here and there in the zoecium. Similar orange 
granules were also observed in the leucocytes. 
Most of the tissues of the polypide, such as the tentacles 
and the several parts of the alimentary canal, have a diffuse 
yellow colour, the pharynx, the circumoral region, and the 
intestine being of a brighter orange-yellow colour. The first 
part of the stomach and the whole of the cecum contain, in 
addition, pigmented granules, the number of which gradually 
shades off towards the region connected with the intestine, 
so that a zone between the two granular parts is devoid of 
granules.! 
II. Tue AssorptTion or Various PIGMENTs. 
A. INDIGO-CARMINE. 
A saturated solution of indigo-carmine in sea-water was 
added to the sea-water containing the living colonies until the 
solution was of such a strength that the animals were not 
easily seen through a thickness of more than one and a half 
inches of the solution. After being left for two or three days 
in this solution the colonies were transferred to ordinary sea- 
water in a tank, and were examined from day to day. It may 
be pointed out that even after this treatment, and in the other 
experiments described below, the colonies remained perfectly 
capable of producing “ brown bodies,” fresh polypide buds, 
and new zoecia at the growing edges of the colony. 
a. Bugula neritina. 
On examining a colony which has been immersed for some 
hours in indigo-carmine, it is at once obvious that while most 
1 The arrangement of these granules is well shown by Haddon in the same 
species (‘Quart. Journ. Micr. Sci.,’ xxiii, Pl. XXXVIII, fig. 12), Haddon 
has identified this species as F. carbasea, and the part of the alimentary 
canal which he has described as “ intestine” (¢z¢.) is the part which I have 
alluded to throughout as “rectum.” 
