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Actinopharynx. I he ectoderm, 28— 40 p thick, has a very great number of the 
large deeply staining glandcells, which are found in the entoderm of Sibopathes gephura. 
Between them and in the upper part of the epithelium the number of nuclei is very large. 
No musclefibres aie visible while the pigment is entirely absent. The actinopharynx descends 
deeper on the side of the sagittal mesenteries than on the side of the transversal mesenteries. 
The mesogloea is extremely thin, usually even invisible since the preservation is rather 
bad. Everywhere the thickness is only a fraction of 1 p.. — The entoderm (26 p.) is the 
same as in tentacles, bodywall, etc. — It is to be remarked that the absence of the actino¬ 
pharynx in Sibopathes gephura might be explained as a seeming absence through the very 
gi eat thinness of the mesogloea. But Sibopathes gephura has in its entire entoderm of the 
body-cavity the same glandcells, which with Schizopathes are only present in the actinopharyngeal 
ectodeim. Besides there are other points, which are in favour of my opinion, viz. absence of 
mesenterial filaments, narrow mesenteries with a free border, a clearly visible limit between 
the entoderm of the gastral cavity and the ectoderm of the oral cone, etc. 
Mesenteries. In the lateral third parts of the polyp only the transversal mesenteries are 
present. The sagittal mesenteries are only to be found in the middle third part of the polyp ; 
they are inconspicuous. I he secondary mesenteries are of even less importance; both pairs 
are only present in the oral cone and they do not descend any farther down than over two 
thirds of the depth of the oral cone. As far as can be made out these secondary mesenteries 
are not attached to the actinopharynx; their border is entirely free on this side. Perhaps this 
is only seeming through the thinness of the mesogloea but in any case the mesogloea of the 
secondary mesenteries is much broader on the side of the bodywall than on the side of the 
actinopharynx. They do not give the impression of mesenteries, which spring from the actino¬ 
pharyngeal wall to be attached only in a secondary manner to the bodywall. On the contrary 
it is more probable that the secondary mesenteries have originated on the bodywall in this 
case. — I he transversal primary mesenteries are also very thin, max. iop. near the bodywall, 
but this value diminishes into a fraction of 1 p. at the side of the actinopharynx. In the lateral 
third parts of the polyp they are somewhat better developed, but not much; here they are 
convoluted (PI. VI, figs. 14 and 16). On none of the mesenteries musclefibres are to be found 
nor mesogloeal lamellae. 
I he mesenterial filaments have the same anatomical structure as the actinopharyngeal 
ectoderm. I hey are single-lobed, and only to be found along the transversal primary mesen¬ 
teries. I hey are very convoluted; pigment is entirely absent. 
Reproductive organs. Ova are only to be found in the transversal primary mesen¬ 
teries; these mesenteries have a swollen part, close to the bodywall; the distal part of the 
mesentery is thin again. This swollen part is the zone, where the ova originate; sometimes 
this swollen part is for a certain distance loosened from the mesentery on the side of the 
bodywall. Ihese ova are to be found in the lateral third parts of the polyps, but in the 
sections through the oral cone ova may also be found in the transversal mesenteries. The 
diameter of the ripe ovum is 400 p.\ the gastral cavity is large enough to contain them but 
they may also be found in the tentacles, which are enormously swollen in such a case. Each 
