148 SIDNEY F. HARMER. 
ever, obvious that the formation of new polypide-buds com- 
mences (and therefore ends) at different periods in the several 
zocecia. 
The account which has just been given of the growth of the 
end of the cecum round the “ brown body,” and of the manner 
in which the latter passes into the lumen of the alimentary 
canal, is supported by the fact that precisely similar processes 
were noticed in fresh zocecia which had not been exposed to 
the abnormal condition of being placed in indigo-carmine.! 
Mr. Newstead did not find that any of the indigo-carmine 
contained in the leucocytes passed with the “ brown body ” 
into the new alimentary canal; and at the end of the series of 
observations (seventy-third day) all the living zocecia still con- 
tained blue-coloured leucocytes. Further observations will be 
necessary to show what is the ultimate fate of these leucocytes. 
It is not impossible that the pigment contained in them may 
be excreted in small quantities with successive generations of 
“brown bodies; ’’ but it appears to be more probable that the 
pigment is simply left behind in the zoccia, 
Bugula neritina and B. avicularia. 
The “ brown body” in these species has a very different 
history from that which has just been recorded in Flustra, 
inasmuch as it is not taken up by the alimentary canal of the 
newly formed polypide. 
In B. avicularia the formation of a new polypide in an 
old zocecium was, in my specimens, comparatively rare. The 
older parts of the colony merely contained ‘‘ brown bodies,” 
smaller masses of pigment, leucocytes, and connective-tissue 
cells of various kinds; and polypides were usually only found 
in the neighbourhood of the growing-points.” 
In B. neritina new polypides are freely regenerated in the 
old.zocecia. They are developed in the middle of a dense net- 
work of funicular tissue situated between the front wall of the 
zocecium (i. e. the surface which bears the aperture) and the 
1 See also Haddon’s account (‘ Quart. Journ. Micr. Sci.,’ xxiii, 1883). 
2 See Hincks, ‘ Brit, Marine Polyzoa,’ vol. i, 1880, p. 52. 
