2 29 
entoderm, is not smooth but sinuous and very much like pseudopodia, whether for fixation or 
nutrition or both. 
27. Stichopathes ceylonensis T. & S. 
Tentacles. The ectoderm (85 y) contains a large number of nematocyst-batteries 
surrounded by deeply staining glandcells, on the top of the papillae but also in the inter¬ 
vening space. The upper layer of the ectoderm contains many oval deeply staining gland- 
cells, with granular contents in the cell-periphery. Homogeneous glandcells, which do not stain 
so deeply, are found in the lower half of the epithelium. The nervous layer is separated from 
the mesogloea by a clear space. There are longitudinal musclefibres. The mesogloea (28 y) 
is homogeneous, with very rare transversal fibrillae. The entoderm (50 y) contains circular 
musclefibres and only a few deeply staining glandcells. 
One of the sagittal tentacles is somewhat deformed. While the base and the top have 
the normal lumen, this lumen is absent in the middle part of the tentacle. The entoderm has 
altogether disappeared, perhaps through parasitic influence. The beginning of such a reduction 
might be the same as in Stichopathes saccula a. o. The mesogloea is changed into a double 
lamella, surrounded by the ectoderm. 
Bodywall. The ectoderm (56 y), the mesogloea (14 y) and the entoderm (50 y) 
have the same structure as in the tentacles, but the musclefibres and the nematocyst-batteries are 
absent. The latter however are to be found in the ectoderm of the oral cone. The entoderm of the 
oral cone contains circular musclefibres. The polyps are separated by an interzooidal septum, 
140 y high, with small secondary mesogloeal lamellae, without corresponding folds in the entoderm. 
The thin axial layers are lost for the greater part. 
Actinopharynx. The ectoderm (40 — 80 y) is folded. It has the same granular gland¬ 
cells as the bodywall, together with the actinopharyngeal glandcells, which, as usually, are found 
in the upper half of the ectoderm, leaving a clear space at the surface. — The actinopharyngeal 
ectoderm forms a lip at the mouth. There are slightly developed longitudinal musclefibres. The 
pigmentation is entirely absent. The mesogloea is 1 y thick, which value increases to 10 y 
in the lower part of the actinopharynx. The entoderm (30 y) is the same as elsewhere. 
Mesenteries. They are normal in number and structure. The secondary mesenteries 
descend to the deepest level on the side of the bodywall. The free border of the primary 
transversal mesenteries is broadened at the polypar periphery, where the mesenterial filaments 
have come to an end. This broadened border contains a rather large number of oval cells in the 
thickened mesogloea, just like PI. I, fig. 10. The longitudinal musclefibres are found unilaterally, 
supported by mesogloeal lamellae. On the primary sagittal mesenteries these fibres are found 
on the sides facing each other in the same pair. On the primary transversal mesenteries they 
are lying on the same side. On the secondary mesenteries they are found on those sides which 
are averted from the primary transversal mesenteries. In tangential sections of the oral cone the 
situation of the longitudinal and transversal musclefibres is the same as in PI. Ill, fig. 8. 
The mesenterial filaments are kidney-shaped and thrice as broad as the mesenteries, 
