2 10 
The axis has a cellular intima; the wall is 40 p. with a diameter of the lumen of 5o p. ; 
nearer the top this values are resp. 7 p. and 33 p.. The spines are 20 p. long- they are hollow, 
often with a granular lumen. The axis-ectoderm is 2 p thick, but 7 p at the base of the 
spines. The mesogloea is less than 1 p,; the entoderm 4 p. The connecting septum is 
short and narrow but in the interpolypar area this septum is more like a fusion of the bodywall 
and the axis-layers, over half of the circumference. — The sheath of layers around the spines 
may be fused with the bodywall; the spines project rather far into the polyps; in one case a 
testes-capsule is indented kidney-shaped by a spine. 
Actinopharynx. As in every examined species, here also the actinopharynx descends 
deepest on the side of the primary sagittal mesenteries but it extends horizontally widest 
along the primary transversal mesenteries. The ectoderm, 33 p thick in the higher part 
of the actinopharynx, diminishes to 25 p in the lower part. Near the free lower border 
the ectoderm is folded deeply with mesogloeal lamellae as supports in the folds. These folds 
may be followed rather high in the actinopharynx. There is a great number of actinopharyngeal 
glandcells and also of hyaline ones. Pigment is entirely absent. The actinopharyngeal ectoderm 
is not continued as a lip out of the mouth. There are no musclefibres. In its lower part the 
actinopharynx touches for some distance at the axial sheath. — Mesogloea (3 p) and ento¬ 
derm (4 p) are of the same structure as in the bodywall. 
The mesenteries are normal in number and situation. Their mesogloea is 2 p, their 
entoderm 3 p thick; musclefibres are entirely absent, while there are neither mesogloeal lamellae. 
The secondary mesenteries descend deeper, partly on the side of the bodywall, partly on the 
side of the actinopharynx. 
The mesenterial filaments are of actinopharyngeal ectodermal structure; they are single- 
lobed, broader than the mesentery. Pigment is entirely absent. Along the transversal primary 
mesenteries they are branched as in PL V, fig. 2. 
Reproductive organs. There are only testes to be found. The greatest diameter of the 
oval capsules is 100 p; they are so large that only 4 or 5 of them are visible in one and 
the same section, filling the available space, while only some of them are fully developed. 
Many of them, but not all, are ripe. In this case the bundle of tails is cylindrical or fan-shaped. 
Sometimes the bundle is composed of secondary ones, as is apparent from the groups of heads. 
Each testis is separately inclosed in a very thin mesogloeal capsule, which is thicker with the 
unripe testes. On several places it can be clearly made out that the testes-capsules are formed 
by invagination of the mesogloea of the mesenteries, so that apparently the testes lie at the 
other side of the mesenteries than where they came from. They are found only unilaterally in 
the transversal primary mesenteries, but not at all in the other mesenteries. — As a divergation 
of the normal condition, testes may be found in the entoderm of the ultimate part of the 
actinopharyngeal border, in the neighbourhood of the transversal mesenteries. This is not so 
very strange, since this part of the entoderm immediately adjoins the mesenterial entoderm, 
which also contains many testes. — In one case I see the top of the bundle of spermatozoa 
emerge from the mesogloeal capsule; probably the spermatozoa are liberated in this manner, 
through the original opening of the invagination, perhaps secondarily opened. 
