ON THE DEVELOPMENT OF LICHENOPORA VERRUCARIA. 131 
explanation of the total absence of brown bodies in old zocecia. 
In L. hispida the alimentary canal probably does not absorb 
the brown body, since a considerable number of old brown 
bodies occur in the proximal parts of the zoccia (cf. p. 97), 
The old polypides are not merely different in size from the 
young ones, but their several parts may be very differently 
arranged, during the retracted condition at least. The polypide 
of young colonies is like that of many other Polyzoa,—e. g. 
that of Alecyonidium as figured by Prouho (18, pl. xxiii, 
fig. 3). The short pharynx lies in the same line as the ten- 
tacles, and from its lower end a long cesophagus passes upwards 
(parallel with the tentacles) to open into the stomach (ef. fig.19). 
The intestine and rectum continue the direction of the ceso- 
phagus, while the caecum hangs down into the body-cavity 
parallel with the cesophagus. The apex of the cecum is formed 
of more protoplasmic cells, but its sides contain the yellow 
granules which have already been mentioned. In the poly- 
pides of old colonies the whole of the cecum is much swollen. 
Its apex has not altered its place, as is shown by the position 
of the group of protoplasmic cells. The upper end of the 
stomach or the region of the intestine is, however, commonly 
bent, so that the intestine and rectum may be directed down- 
wards (away from the orifice of the zocecium). The walls of 
the cecum are at the same time greatly swollen and very 
granular. The lumen may be in places quite obliterated; and 
in any case, parts of the wall have no sharp inner boundary. 
The epithelium here shades off quite gradually into the granular 
contents of the stomach. This might be ascribed to defective 
preservation, were it not for the fact that other parts of the 
same sections are well preserved. But since, in many cases, 
no polypide-buds are being formed, and since none of the 
zocecia are losing their polypides, I believe that this is an 
arrangement by which none of the zocecia are rendered in- 
efficient for nutritive purposes during the time at which there 
is the greatest strain on the energies of the colony. 
The phenomenon which has just been described appears to 
be characteristic of old colonies (Stage G and later stages), but 
