53 
Figure 5 is a section through a portion of a cyst. 
“The outer, celomic, side of the gut-wall lies to the right, 
and the muscle-layers, though a little thin, perhaps, are 
free from infection, and present no feature worth drawing. 
At the left is a fold (endoth.) of the mucosa, also quite 
normal, at the head of a furrow. At ect., ect. 1s seen the 
thick, practically structureless external layer (ectoplasm ) 
of two adjacent cysts, which are separated by a 
few delicate layers of connective-tissue (areol. tiss.). 
Hagenmiiller, who maintained that the cyst membrane 
is formed of elements belonging to the host, was cer- 
tainly referring to pseudocysts, which, however, he did 
not recognise were intimately connected with diffuse 
infiltration. He does not seem to have seen true cysts at 
all. In these, there is no transition whatever visible 
between the surrounding tissue and the firm ‘“‘ectorind” (as 
one may term the modified ectoplasm) of the parasite, nor 
any signs in this latter of flattened-out nuclei or cells. 
I entirely agree with Thelohan in thinking that the cyst 
membrane is a modified ectoplasm, and for this reason 
propose the term ectorind, to distinguish it from an ecto- 
eyst. Against its being an ectoplasmic secretion——com- 
parable to the cyst-envelopes of Gregarines—I would say 
there is no other layer which can be regarded as the ecto- 
plasm. Immediately internal to the ectorind is a delicate 
layer without any sign of spore-formation, but which is 
structurally identical with the endoplasm into which, 
indeed, it passes, and, therefore, I regard it also as such. 
(In some sections through a Glugea anomala, from a 
stickleback, which I possess, there is an equally distinct, 
here finely-striated, ectorind, thus confirming Thelohan’s 
fies. 158 and 159, pl. 9). Internal to the ectorind, and ex- 
tending all round, we see the typical Myxosporidian endo- 
plasm (end.). It is a comparatively narrow layer, as by 
