224 
may be more numerous locally. The nervous layer is almost in contact with the mesogloea. 
There are no musclefibres worth mentioning. The mesogloea (20 u.) is variable in thickness. 
I here are sporadical oval or round cells and there may also be transversal fibres between 
ectoderm and entoderm, but not many. The entoderm (56 p) has an indistinct nervous 
layer, but no musclefibres. There are not many glandcells; they are principally of the hyaline type. 
The bodywall, the layers of which are resp. 56, 14 and 42 p thick, has the same 
structure as the tentacles. The ectoderm contains a greater number of hyaline glandcells and 
nematocysts, which may be single or collected in little groups of a few only. The entoderm 
has a somewhat greater number of deeply staining glandcells than the tentacular entoderm. 
The layers of the oral cone are thicker. 
The Axis-epithelium is lost for the greater part. The layers are resp. 4, 7 and 15 p. 
The actinopharynx does not descend much below the base of the oral cone. The lumen 
is slit-like. The ectoderm, which is very rich in actinopharyngeal glandcells, is curved out¬ 
wards at the mouth as a lip. There is no pigmentation. The ectoderm is sub-regularly folded, 
one fold at each connective point of a mesentery, and one in the intervening space between 
two connective points. At the sagittal ends there is only a single triangular fold between the 
two sagittal mesenteries. The folds are 125 p thick, while in the grooves the ectoderm is only 
60 p. The folds increase in number in the lower part of the actinopharynx. At the base of each 
fold the mesogloea is thickened, and the epithelial cells radiate from here. There is a large 
number of hyaline glandcells, especially in the deeper layers of the ectoderm. There are very 
distinct longitudinal musclefibres. — The mesogloea, 7 p thick, increases to 21 p at the 
base of the ectodermal folds. The entoderm (25 p) has circular musclefibres, which are more 
strongly developed than the ectodermal muscle-system. The entodermal structure is the same 
as in the bodywall, but the glandular elements are rather scarce. 
The mesenteries, which are normal in number, bear unilateral mesogloeal lamellae with 
slightly developed longitudinal musclefibres. They are not to be found on the primary sagittal 
mesenteries. On the primary transversal mesenteries the musclefibres are situated on the same 
side of both mesenteries; on the secondary ones the musclefibres are found on those sides 
which are averted from the primary transversal ones. 
In tangential sections of the oral cone the mesenteries sometimes show a bilateral system 
of musclefibres, just as is the case in PI. Ill, fig. 8, according to the part of the mesentery 
being nearer the bodywall or nearer the actinopharynx. In those parts of the mesenteries, which are 
farthest from the polyp-centre the musclefibres on both sides of the mesentery are parallel with 
one another. — The secondary mesenteries descend a little more deeply on the actinopharyngeal 
side than on the side of the bodywall. 
I he mesenterial filaments are single-lobed and to be found along all the mesenteries, 
but along the primary transversal mesenteries only they are convoluted and branched, especially 
near the free border of the actinopharynx. There is no pigment. They are encased in a cup¬ 
shaped entoderm as in PI. II, fig. 6. 
Reproductive organs (PI. VI, fig. 11). There are ova in the primary transversal mesen¬ 
teries. They are large and not numerous. They fill the greater part of the gastral cavity, but 
