205 
This swollen border increases continually till it takes up half the breadth of the mesentery. 
In this swelling the mesogloea contains a great number of oval cells (one of them is white 
in PI. VI, fig. 5). The normal mesogloea of the mesenteries is less than 1 u. in thickness. The 
transversal mesenteries are very thin when you compare them with the mesogloea of the lateral 
tentacles in PI. VI, figs. 5 and 9. 
Mesenterial filaments are entirely lacking, as is natural since there is no actinopharynx. 
Reproductive organs. There are ova present, only in the transversal mesenteries. Each 
ovum is surrounded by a mesogloea] sheath ; the thickness of this capsule is only 3 p with the 
ripe ova, but 7 p with the younger ones (PI. VI, figs. 9 and 15). The diameter of the ripe ova 
is 200 p; one single ovum may fill the entire lumen in a section of the polyp, at least near 
the top of the colony. I he nucleus is large with a round, finely granulated nucleolus. Since 
there is usually hardly any gastral cavity the ova are found in the lumen of the tentacles, 
always in one of them, so that one of the tentacles is very much swollen (PI. VI, fig. 15) 
and the polyp is asymmetrical. The ova are found behind each other in a longitudinal row 
in the swollen border of the mesenteries, so that the narrow part of the mesentery is always 
clearly visible above the ova. — Sometimes two or three ova are found in the same section 
(PI. VI, fig. 15), but then they are lying beneath each other in the mesentery, which is curved 
towards one side in the base of the tentacle. I he capsule of the ovum, or, when there are more 
ova present, of the ovum which is nearest the free border of the mesentery, may be fixed to 
the mesogloea and the entoderm of the tentacles or the bodywall. Very likely the ova are 
liberated by the bursting of the capsule, for repeatedly empty capsules are found with collapsed 
walls (PI. VI, fig. 9, indicated by an asterisk). They are connected with the neighbouring 
ovarial capsule (in fig. 9 this connection is not attained by the section). — The ovum does 
not fill the entire lumen of the capsule, but perhaps the preservation has caused a contraction 
of the ovum. There is nothing to be seen of the enclosing of the ova in their capsule ; the 
propensity for filling only one tentacle is an indication of a unilateral forming of the ova, so 
that the mesentery is lop-sided. 
1 he described species is very primitive in structure, as is apparent from its having no 
actinopharynx, many large deeply staining glandcells in the entire entoderm instead of a con¬ 
centration of them in an actinopharynx, no secondary mesenteries, only very narrow primary 
mesenteries, no mesenterial filaments; perhaps the very unimportant mesogloea may also be 
reckoned as a primitive character, just like the very broad connection between the axis-epithelium 
and the bodywall. 
11. Schizopathes ciffinis (Br.) emend. (PI. VI, figs. 1, 14 and 16). 
Tentacles. The ectoderm, 55 p thick, has nematocyst-batteries, which extend almost 
to the base of the ectodermal layer; they are surrounded by homogeneously deeply staining 
glandcells, which are also rather high. The nervous layer is not very well visible, while muscle- 
fibres are entirely absent. The mesogloea, 7 p thick, is homogeneous; very rarely some 
oval cells occur. In some places the mesogloea is fibrillose, but these fibres are parallel with 
