2 2 2 
Towards the top of the colony the axis-ectoderm increases in thickness and becomes a cylindrical 
epithelium. The axis itself is not round in section but irregularly starshaped through the originating 
young spines, in which the axial lumen is continued as a narrow slit. Here the axis is very 
much like the top of the axis of Dendrobrachia fall ax Brook. Still further towards the colony-top 
the entire axial entoderm is in contact with the entoderm of the bodywall and furtheron both 
entodermal layers are fused together, for the greater part of its circumference. Even the last 
section through the top contains horny parts in the middle of the section. So the ectodermal 
invagination, in which the axis originates, takes place exactly at the extreme point of the 
colony, and not at a little distance from the top as is observed in other cases. — There is 
no single cylinder of ectoderm, mesogioea and entoderm to be found, in which the axis has 
not yet appeared. 
Actinopharynx. .The actinopharyngeal wall itself is very deeply folded, especially in 
those parts of the free border, which are attached to the primary transversal mesenteries. These 
parts are curved either dorsally or ventrally, so that those parts of the free border are almost 
in contact in the median plane. In the distal half of the polyp these curved parts of the 
actinopharynx even give origin to an entirely closed canal, a sort of glyphe but without a 
specific anatomical-histological differentiation. The ectoderm (22 p.) has a great number of 
actinopharyngeal glandcells, but no other deeply staining ones. There is no pigmentation. In 
the mouth the actinopharyngeal glandcells are very much crowded and also in its immediate 
vicinity, at the exterior. In one specimen there are also glandcells of the nematocyst-battery- 
type in the last named locality. — The entire ectoderm is very much folded longitudinally, 
also in the “glyphe”; these folds are secondary ones of the folds described with the entire 
actinopharyngeal wall. The mesogioea is less than 1 p.; the entoderm (5 p.) has the same 
structure as elsewhere. 
Mesenteries. They are normal in number and course. The entoderm is 6 p., the meso¬ 
gioea 1 ij.. There are no musclefibres, but the primary transversal mesenteries have very slightly 
developed longitudinal mesogloeal lamellae on one side of the mesentery. 
The mesenterial filaments are found along the primary transversal mesenteries only. 
They are not in continuity with the actinopharynx for the latter part of the polyp has entirely 
disappeared in the series of sections for a distance of some 10 p„, before the filaments appear. 
They are convoluted and branched. They project far into the tentacular lumen. There is no 
pigmentation. They are single-lobed and kidney-shaped; the mesentery broadens gradually into 
the breadth of the filaments. The mesogloeal fork-ends are at right angles with the mesenterial 
mesosdoea. There is also ectoderm to be found at the mesenterial side of the fork. 
There are no reproductive organs. 
23. Parantipathes columnaris (Duch.) Br. 
Tentacles. The ectoderm (18 p., but somewhat less at the base of the tentacles) 
contains large, deep nematocyst-batteries, which may project as a dome from the surrounding 
epithelium so that papillae are formed of a battery and nothing more. — They are surrounded 
