number as their muscle-system, in the sexual cells, the musclesystem in general, etc. Apart from 
the differences between the described species, which differences are to be found on almost 
every point of the microscopical anatomical characters as the structure of the epithelial layers, 
the musclesystem, the course and the number of the mesenteries, the shape of the actinopha- 
rynx, the mesenterial filaments, etc. the following characters are of a more or less general 
value; however these characters are very unstable. 
Ientacles. Ectoderm. Hardly any element may be mentioned as always present. As 
a rule the epithelial layer contains many ciliated cells; the glandcells may be of the hyaline 
type or of the deeply staining type. The latter are crowded together in groups and of a 
lighter shade, or they are independent and very deeply staining with granular or homogeneous 
contents. 1 he latter types are usually to be found around the nematocyst-batteries. Next to 
species with hyaline glandcells only '{Eucirripathes Rumphii , Sibopathes gephiira), other species 
are to be found with a few deeply staining glandcells around the batteries only, or with this 
same type also in the rest of the ectoderm, either sparingly distributed or much crowded or 
with every type of glandcells (. Eucirr . spiralis var. aplianipathoides ), etc. in every combination. 
Several species have nematocyst-batteries of a conical shape, usually with one type of nema- 
tocysts, rarely with two types; the batteries are found on the top of the ectodermal papillae, 
but sometimes in the intervening ridges also. — Below these batteries there is an accumulation 
ot nuclei; the batteries themselves may be surrounded by deeply staining glandcells or not. 
There are no single, independent nematocysts. While there are species without nematocyst- 
batteries, there are other species, where these batteries are developed to such an extent as to 
fill almost the entire ectoderm. The battery may take up part of the thickness of the ectoderm, 
but they may also reach to the base of this layer ( Schizop . apjinis). In rare cases the ectoderm 
contains a large quantity of pigment (. Euant . mynophylla). The ectodermal nuclei are always 
deeply staining, small and oblong. 
L sually the nervous layer is easily to be distinguished, but on a very variable depth in 
the ectoderm, sometimes in contact with the mesogloea, sometimes separated from the meso- 
gloea by a clear space. In the same species both modes of occurrence may be found {Euant. 
dichotoma , Aphanip. Sibogae). Rarely nyclei are to be observed in this layer, as an indication of 
^ ^ c , v hich is entirely absent in some species, may be more or less 
strongly developed with other species. It consists of longitudinal musclefibres, which are often 
supported by small mesogloeal lamellae. 
Mesogloea. Several species have a homogeneous mesogloea. In other species this 
lay ei repeatedly contains connective-tissue cells. Usually these cells are oval or round but never 
stellate. They are especially to be found in the thicker parts of the mesogloea while the 
thinner parts in the same species may be homogeneous. These cells are of ectodermal origin, 
as was clearly visible in Sibopathes gephura , where they are also found in the base of the 
ectoderm, and where the connecting canals through the mesogloea towards the cells are still 
in existence. Besides there are repeatedly fibrillar connections between the ectodermal and the 
entodei mal base, especially at the base of the tentacle, where the tentacle-wall is continued 
by the bodywall. These fibres may show swellings. Usually their course is straight, seldom 
