2 37 
irregular, ihey may be also parallel or subparallel with the ectodermal base. In rare cases 
there are thicker bundles, which may be artefacts however. — The thickness of the mesogloea 
is not so typical for a genus, as is supposed by Roule. There is no relation between the 
support, which may be given by the spines or not, and the mesogloeal thickness. With Eucirr. 
Rumphu the thickness of ectoderm and mesogloea is respectively 115 p. and 7 v, while with 
Eucirr. trans/ucens these values are resp. 105 p. and 140 p. According to Roule’s supposition 
the latter species, which sometimes even has a much thicker mesogloea, ought to have very 
slightly developed spines, while the figures in the systematic part show the spines of Eticirr. 
translucens as much as thrice as long as with Eucirr. Rumphii. But apart from this fact, 
the very unequal thickness of the mesogloea in the different species of one and the same 
genus is not well in accordance with the supposition that unbranched colonies or colonies 
without spines or with small spines have a thicker mesogloea than branched genera or colonies 
with well developed spines. Aphanipathes Sibogae has a thick mesogloea; Sibopathes geplmra 
combines a very thin mesogloea with very small spines and the same is true for Bathypathes 
patula a. o. — I he mesogloeal surface may have small lamellae for ectodermal and ento- 
dermal musclefibres; the entodermal side often shows circular ridges, especially near the base 
of the tentacle, sometimes bearing secondary ridges. 
Entoderm. I he epithelial layer contains many ciliated cells and especially hyaline 
glandcells, but no deeply staining glandcells or a few only. The entodermal nuclei are larger 
and less stained than the ectodermal nuclei, and round. The number of deeply staining gland¬ 
cells is large in Sibop. gephura but possibly this fact is to be connected with the absence of an 
actinopharynx. Parant. columnaris also shows a large number of alveolar deeply staining gland¬ 
cells in the entoderm. — The muscular layer, which in many cases is entirely absent, consists 
of circular fibres, which are less developed than the ectodermal system. The fibres may be 
supported by mesogloeal lamellae. 
Bodywall. In the main the structure of its layers is the same as of the tentacles, but 
the nematocyst-batteries may be entirely absent, except in some species such as Sibop. gephura , 
Schizop. ajfinis , Euant. plana , etc. where their number is even very large. Usually the nema¬ 
tocyst-batteries are very numerous in the oral cone, especially near the mouth, just like the 
deeply staining glandcells, but not as a rule. Very rarely single nematocysts are found in the 
ectoderm. The deeply staining glandcells may be locally entirely absent, and locally crowded 
as palisades, in one and the same species. The glandular elements in the oral cone are often 
more developed than in the rest of the bodywall, but usually less than in the tentacles. The 
entoderm (Eucirr ip at lies- species) as well as the ectoderm (Euant. myriophylla , Stichop. variabilis 
var. asperispina) may contain accumulations of pigment here and there, which in other cases 
otherwise are often characteristic of the actinopharyngeal ectoderm and the mesenterial fila¬ 
ments. — The muscle-system is rarely well developed; the ectoderm may contain longitudinal 
fibres and the entoderm, especially of the oral cone, circular fibres. 
Between the polyps an interzooidal septum may often be found, with several incomplete 
septa on both sides. These secondary septa consist of mesogloeal lamellae only, however without 
the entoderm following these lamellae ( Cirrip ., Hillop. ramosa). These interzooidal septa remain 
