the oral cone. The ectoderm -folds have no connection with the situation of the mesenteries. 
The ectoderm is no pi, but 26 p between the folds. At the sagittal ends of the lumen the two 
folds are shorter with a broader base; there are 4 folds in each half of the actinopharyngeal wall, 
so ten in all. — Just below the surface there is a great number of actinopharyngeal glandcells 
and numerous small nuclei. In this deeply staining layer there is a great deal of brown pigment 
besides. — This pigmentation, which in the upper part of the actinopharynx is only locally 
crowded and even may be entirely absent, increases in the lower part of the actinopharynx. 
The free border contains so much pigment as to blacken the folds entirely, which are more 
numerous here. The nervous layer is well developed and below it there are a number of paired 
deeply staining stripes, at right angles with the mesogloea. I hold them to be thin mesogloeal 
lamellae, covered on both sides by a very thin layer of longitudinal musclefibres. The m eso- 
aloea is 3 u; the entoderm is' the same as in the oral cone. 
Mesenteries. They are normal in number; the primary transversal mesenteries have a 
very convoluted course. The mesogloea is 5 p or less in the higher part of the oral cone and 
slightly more below the free border of the actinopharynx. The entoderm of the primary trans¬ 
versal mesenteries contains pigment, increasing in quantity in the lower parts of the mesentery, 
especially near the bodywall. There are no musclefibres, while mesogloeal lamellae are absent also. 
There are no reproductive organs. 
The mesenterial filaments are found along the primary transversal mesenteries; they 
are very much convoluted and branched. The very thin and fibrillar mesenterial mesogloea is 
slightly broadened and than immediately branched in a large number of fibres, which diverge right 
and left towards the most deeply staining parts of the filament. The mesenterial entoderm, which 
is entirely free from glandcells, surrounds the filament laterally cup-shaped (PI. II, fig. 6). They 
are single-lobed. The pigmentation is very strong, especially on the limit against the entoderm. 
But the periphery of the ectoderm is also pigmentated, although less so; there is some pigment 
also in the basal part of the epithelial cells. There are some hyaline glandcells at a deep 
level, but further especially actinopharyngeal glandcells in the superficial layer. There are no 
nematocysts. — A nervous layer is not to be discerned. 
4. Eitcirripathes contorta v. Pesch. 
Tentacles (PL III, fig. 3; PI. V, figs. 1 and 4). The ectoderm is 80 p. at the base 
of the tentacle and 26 p. at the top. It contains rather numerous deeply staining glandcells, 
with granular contents, especially in the upper half of the ectoderm. In large parts these cells 
are less numerous. There are small hyaline glandcells in the lower half of the epithelium. The 
nematocyst-batteries are to be found only on that side of the tentacle which is directed towards 
the oral cone, and especially on the lower half of the tentacle. The nervous layer is well 
developed. There is a very slight layer of longitudinal musclefibres. The mesogloea, 13 pi 
at the top of the tentacle and 70 p, at the base, has circular ridges on the entodermal side 
(PI. V, figs. 1 and 4), especially in the lower half of the tentacle. — The mesogloea contains 
no oval cells but a large number of very fine fibrillae, which connect in bundles the bases of 
