2 I 7 
Parasites. In one of the series of sections there are numerous unicellular parasites (?). 
At first they give the impression of being ova, but the small nucleus, the large vacuole, their 
independence from the entoderm prevent this opinion. Their plasma is granulated; the globular 
nucleus has a diameter of 12 p in a cell, the dimensions of which are 50 X 80 X no p. — Often 
there is a large vacuole in the cell; the vacuole-diameter is 40 p with cells of resp. 60 X 70 X 40 p 
and 70 X 130x 80 p. The cell is surrounded by a very thin membrane. They are never found 
in the entoderm, but always loose in the gastral cavity, and especially in the lumen of the 
tentacles. These parts of the polyps are not swollen, but the adjoining entoderm is reduced 
to a thinner layer, but not always. There are no further changes. Sometimes there are several 
parasites in the same tentacle and there are always a great many in the same polyp. 
18. Eua n t ip a thes a dies (Gr a y) . 
Tentacles. The ectoderm (33 p) has nematocyst-batteries on the top of the papillae, 
with a surrounding of not very numerous, small, deeply staining glandcells. The hyaline gland- 
cells are much more numerous. ■—- The nervous layer is very deeply seated, so that there is 
no sharp limit between it and the mesogloea. There are no musclefibres. The mesogloea 
(3 p) is homogeneous, and only slightly fibrillar at the base of ectoderm or entoderm. The 
entoderm (10 p) has a few deeply staining glandcells and many hyaline ones. There are 
very slight circular musclefibres. 
Bodywall. The ectoderm (16 p) has the same structure as in the tentacles, except 
for the batteries. There are no musclefibres. The mesogloea (2 p) and the entoderm 
(8 p) are the same as in the tentacles. An interzooidal septum is not to be made out with certainty. 
Axis. The ectoderm (4 p) has some deeply staining elements; the mesogloea is 
less than 1 p; the entoderm is very thick for an axis-entoderm, viz. 20 p and even more 
at the base of the spines; at the top of the spines this layer is still 10 p. The connecting 
septum is short and very broad. 
Actinopharynx. For the greater part this is a straight tube, slightly distally inclined. 
The ectoderm (20 p) has many actinopharyngeal glandcells, but no pigment. The other 
layers are resp. 1 and 6 p. — There is no lip ; the ectoderm of the oral cone is somewhat 
thicker than in the rest of the bodywall. 
The mesenteries are normal in course and number; they have no musclefibres; the 
layers are 10 p (entoderm) and 2 p (mesogloea). 
Mesenterial filaments occur along the primary transversal mesenteries; they are con¬ 
voluted but unbranched (?). They are single-lobed, while the mesenterial entoderm broadens 
gradually towards the filaments. In the basal part of the filaments the same cells occur as in 
the same place in PI. IV, fig. 1. There are no ova or testes. 
19. Euantipatlies japonica (Brook) emend. 
Tentacles. The ectoderm (33 p) is a little like the ectoderm of Eucirripatlies Rumphii. 
There is a great number of nematocyst-batteries (but only with one type of nematocysts) situated 
28 
SIBOG A.-EXPEDITIE XVII. 
