208 
ovum is enveloped in a very thin membrane, visible in PI. VI, fig. 14, to the left, near the 
opening of the invagination, separated from the proper mesogloea-capsule, which is less 
than 1 p in thickness. This capsule is thinner in young ova, especially in that part, which is 
farthest from the invagination-opening (PI. VI, fig. 16). The ova get their mesogloeal capsule 
by invagination; with the ripe ova there is no trace of this invagination to be seen but with 
young ova (PI. VI, figs. 14 and 16) the opening of the capsule is clearly visible, which is 
shut in a later state. 
There are no parasites to be seen. — On one place the bodywall is ruptured by a 
long narrow slit, parallel with the colony-axis, at a little distance beneath the base of the ten¬ 
tacles ; the ectoderm of the bodywall is partly grown inwards, as is demonstrated by the 
colouring of the epithelium. 
' -»* 
12. Eubcithypathes pahila (Br.) emend. 1 ). 
In all the series of sections the ectoderm of tentacles and bodywall has entirely disappeared. 
The entoderm is also very much damaged, to such a degree that only with a certain reserve 
data can be given of the internal structure of the polyps. To this should be added that the 
mesogloea is rather thin on many places, so that usually this indication of the situation of the 
parts of the polyps is not very clear. — Only the following data may be given : 
Tentacles. The mesogloea, 6 p thick, diminishes to 3 p at the top of the tentacles. 
This layer is homogeneous and there are no lamellae for musclefibres. The mesogloea is thinner 
than that of the bodywall! The entoderm is thick, so that there is no lumen in the tentacles, 
but it is possible that the maceration makes the entoderm looser and broader. I here are no 
deeply staining glandcells, but very numerous large hyaline glandcells. 
Bodywall. The mesogloea is 10—23 p. thick; the thickest parts are found between 
the base of the tentacles and near the connecting septum of the axis. I he thickness diminishes 
towards the oral cone. The entoderm is the same as in the tentacles. No interzooidal septum 
is to be found. 
The oral cone has a mesogloea of 4 p, and the same entoderm as in other cases. 
The axis has a wall of 26 p. with a diameter of the lumen of 150 p. ; near the top of 
the branch these dimensions are 7 p. and 250 p.. The spines (66 p.) have no basal lumen. 
There are no fusions to be seen between the layers round the spines and the bodywall. The 
axis-entoderm is 3 p. (12 p. near the base of the spines), the mesogloea 3 p. and the 
entoderm 9 p. The connecting septum is short and broad or triangular with its top fixed 
to the bodywall. This septum lies asymmetrically, not precisely opposite the mouth. The 
mesogloea of the bodywall shows an indentation at the ectodermal side opposite the con¬ 
necting septum. 
The actinopharynx is not clearly visible; probably it is broadened in the middle third 
part of the polyp. The mesogloea is very thin. Pigment is entirely absent. 
1 ) Specimen of station 88. 
