BULLETIN OF THE 
4 
nearly to a straight line, The point at which the upper and lower 
curves most nearly approach each other is where the separation of two 
individuals takes place; that at which they are farthest apart is the 
middle of the zoccium, occupied by the polypide and sexual organs. 
The outlines of the young zoweia are straighter, and their breadth is 
considerably less than that of the adult. 
From what we have already seen, the method of growth of the stock is 
perfectly evident: it is by the formation of new median buds at the tips 
of existing branches, and of new branches from lateral buds. In order 
to understand the origin of the individuals of the primary branches, to 
which subject we will first turn our attention, we must study the tips 
of the branches. 
9. HıstoLogy or tim Buppine REGION. 
Figures 7-9 will serve to show more in detail the method of formation 
of new terminal individuals. We find in these cases one polypide already 
pretty well developed and attached to the body wall by means of the kamp- 
toderm at about the point at which the pyramidal muscles (mu. pyr.) 
are seen to be forming. That portion of the animal which extends from 
about the region of formation of the muscles to a point a little proxi- 
mad of the tip represents the region which will go to form the new in- 
dividual. The tip itself, for reasons which will presently appear, is not 
to be included in the terminal individual. The tip of the branch is to 
be regarded as homologous with the margin of the corm in corm-building 
genera of Gymnolemata. Figures 7-9 (gn.) also show the position of 
the bud which is to produce the polypide. By consulting first Figure 9, 
in which the polypide bud is apparent, the significance of the swellings 
of the body wall in Figures 8 and 7 becomes clear. 
Figure 14 (Plate II.) represents a stage in the development of the 
polypide bud, somewhat later than that shownin Figure 9, and this may 
serve us as a starting point in our study of the origin of a new individual, 
and, first of all, of the new polypide. The whole of Figure 14, from the 
tip down to the neck of the older polypide (cev. pyd.), may be divided, for 
convenience, into three zones: first, that distad of the young bud, which 
may be called the tip of the branch (Fig. 14, a to B) ; secondly, the region 
of the bud itself, which may be called the gemmiparous zone (B toy); aud 
thirdly, the region between this last zone and the neck of the older poly- 
pide, which, for want of a better name, may be called the proaimal zone 
(y to 8). In the formation of a new polypide between a and £, that 
region will in turn become divisible into the three zones just named, 
