Davenport. — Budding in Bryozoa. 
Fig. 96. 
Fig. 97. 
Fig. 98. 
Fig. 99. 
PLATE XI. 
ABBREVIATIONS. 
cev. oe. Neck of occium. ms’drm. Mesoderm. 
cal, Colom. 008, Ocecium, 
ec’drm. Ectoderm. ov! Oöblasts. 
en’drm. Entoderm. pyd. Polypide. 
ex. Outer layer of bud. sto. Stolon. 
i. Inner layer of bud. tet. Roof of stock. 
lu. gm. Lumen of the bud. 
Fig. 98. A portion of a longitudinal section through a young stock of Plumatella 
polymorpha, about two weeks after hatching from statoblast (killed 
12th May, 1890), showing the body wall just analward of the neck of 
a young polypide (pyd.), at the oral side of which a younger bud has 
already arisen. ‘The inner (mesodermal) layer of the body wall 
shows oöblasts (ov.’) in various stages of development. X 600. 
Fig. 94. Longitudinal section of o@cium of Cristatella showing embryo which is 
giving rise to the colomic epithelium by ingression of cells at its 
proximal pole, —i. e. the pole nearest the neck of the owcium. There 
are in the next section two other cells in the cavity of the blastula, 
one of which appears degenerate in that it contains a huge vacuole, 
and has no distinct nucleus, the chromatic substance lying scattered 
loose near the cell wall. x 600. 
Fig. 95. Longitudinal section through ocecium of Cristatella and its contained em- 
bryo. One polypide bud and the stolon (sto.) are shown here. There 
are two other buds in the embryo further developed than this one, 
lying to one side of it, and on the side of each of these buds is the 
Anlage of another. The stolon is seen to be well developed, lying be- 
tween the ectoderm and mesoderm throughout the region bounded 
by the three older buds, and extending as a zone beyond them, and 
even beyond the Anlage of the youngest polypides. The embryonic 
tissue thus forms a disk about 75 X 150 u in extent. >< 390. 
Transverse section of omeium of Plumatella, showing origin of first pol- 
ypide. Compare with Figure 99, which represents an earlier stage. 
x 390. 
Longitudinal section through omeium and contained embryo of Cristatella. 
The stolon is already cut off from the ectoderm. This stage imme- 
diately follows that of Figure 101, Plate XII. The forming bud is 
that of the first polypide. 890. 
Oblique section through oœcium of Plumatella, showing a later stage in 
development of the inner layer of the larva (cf. Fig. 94). X 600. 
Longitudinal section of oæcium and contained larva of Plumatella, The 
bud shown at i, ex. is the first in the colony. An incipient (second) 
bud is shown five sections to one side in the region indicated by an 
asterisk. X 410. 
