72 
has been figured by Lang (1884, Taf. 31), Heath (1907), and 
Heath and Mc Gregor (1912), and my own experience stretches 
over most of the Polycladidean families. All these investigations 
point in the same direction, thar such a discrete marginal nerve 
is lacking. A kind of sub- 
stitute for it might be found 
only in the density of the 
network along the border, but 
the nerve branches are at the 
same time more narrow. 
In the genital system 
I was not able to detect any 
clear difference from the type 
specimen. It might only be 
added to the previous descrip- 
tion (Bock 1913, pp. 165-166) 
that in the prostatic vesicle 
the glandular layer has an 
even contour and is conse- 
quently unfolded. It reaches 
the same thickness as the 
muscular envelope. There is 
only one kind of secretion in 
the intra- as well as extra- 
capsular giands. The granules are of uniform and extreme fineness 
and imbibe feebly with eosin, attaining a duil pink tint. Thus the 
second kind of giands producing a large-granular, intensively stain- 
able secretion is absent. Just at the proximal part of this vesicula 
granulorum the lumen is widened, the lining epithelium being low 
and glandless. In a number of Acotyleans (e. g. Stylochus-speciesy 
Cryptocelis ijimai Bock 1923) the interior wall of the vesicula 
granulorum is differentiated into a low glandless epithelium at the 
lumen and a basal layer of accumulated bodies of giand cells. No 
trace of such differentiation occurs here. 
The male genital apparatus of Emprosthopharynx undoubtedly 
resembles in structure that of the genus Cestoplana, even if certain 
differences as in the presence or absence of penis-sheeth, occur. 
In both genera the vesicula granulorum opens by means of a duet 
Text-fig. 22. Emprosthopharynx opistho- 
poriis. Nerve net around the male apparatus. 
prv, vesicula granulorum; vs, vesicula 
seminalis. 
