458 
EDITH M. MUSGRAYE. 
the middle of the rachis. As in the case of Pennatula 
the coloured solution was immediately ejected in continuous 
streams from the autozooids and siphonozooids, indicating a 
very brisk circulation of fluid within the colony, the direction 
of the currents being mainly exhalent. 
Within a very few minutes the methylene blue streamed 
from several basal pores which then became evident. These 
pores had taken no part previously in the expulsion of the solid 
particles of carmine. Several of the pores are indicated in fig. 3. 
In all cases the injection of a coloured fluid into the 
dorsal canal was immediately followed by its distribution to 
all parts of the colony and expulsion from autozooids and 
siphonozooids, and, indeed, after a very few minutes from the 
basal and dosal pores. 
Upon examining a dilatation in the region of the stalk, 
which appeared in a specimen of Pteroeides shortly after 
an injection had been made, the coloured fluid was found in 
considerable quantity in the “spongy tissue” of this 
particular region of the colony, giving evidence in support 
of the supposition of its distensibility, in assisting- in the 
dilatation and contraction of the colony (pp. 463, 464). 
These facts afford an interesting illustration of the extreme 
rapidity and comprehensiveness of the circulation of fluids 
within the colony under what appear to be normal conditions. 
In the case of the injection into the dorsal canal of the 
rachis of powdered carmine suspended in sea-water, the distri- 
bution of these solid but minute particles proceeded much 
more slowly. In the case of Pennatula the injecting fluid 
was transferred immediately to the base of the stalk, but the 
subsequent ejection of carmine particles did not take place 
from autozooids or siphonozooids until several hours had 
elapsed, and after a still further interval from the basal 
apertures and dorsal pores. 
In Pteroeides the interval between the injection and 
extrusion of carmine extended over twenty-four hours. Its 
ingestion in minute quantities and subsequent protrusion 
from the cells lining the canals may to a great extent be 
