A412 WILLIAM NICOLL. 
These are obviously not prostatic cells, for they present a 
different appearance and take on a distinctly. blue stain. 
Moreover, ducts cannot be made out. Various functions 
have been ascribed to these cells. Most frequently they have 
either not been noted or considered to be prostatic cells. 
They have also been regarded as glands opening into the 
ductus ejaculatorius. Neither of these theories has been 
verified. The staining reaction differentiates them from the 
prostate cells and from similar cells, e.g. those of the shell- 
gland. On the other hand, they bear a distinct resemblance 
to the circum-cesophageal and peri-vaginal cells, as also to the 
“subcutaneous gland. cells” (i.e. myoblasts). The resem- 
blance to the cireum-cesophageal cells, which Bettendorf has 
shown to be the myoblasts of the cesophageal muscle-fibres, 
suggests that the cells surrounding the ductus ejaculatorius, 
as also the peri-vaginal cells, are the myoblasts of the muscle- 
fibres of the walls of these structures. 
The ovary is an almost globular body situated close behind 
the ventral sucker and a considerable distance in front of the 
anterior testis. It may lie on either side of the middle line, 
or, according to Olsson, it may be median. In none of my 
specimens did it occur in the latter position; it was most 
frequently on the left-side. The size is °23 by *19 mm., the 
thickness ‘16 mm. The configuration of the shell-gland 
complex has already been carefully described by Blanchard. 
Just behind the ovary lies a small oval receptaculum seminis. 
From its inner side there arises a duct giving off Laurer’s 
canal, which is a straight tube of moderate length, and then 
running forwards to join the oviduct. The latter issues from 
the inner surface pf the ovary, and passes backwards. After 
being joined by the duct from the receptaculum seminis, it 
turns forwards to pass into the ootype, and thence into the 
uterus. Blanchard’s representation of the shell-gland is 
somewhat diagrammatic. It is much more extensive and is 
vot enclosed within a membrane. It lies under the dorsal 
| “ Uber Muskulatur und Sinnezellen der Trematoden,” ‘ Zool. Jahrb. 
Anat.,’ x (1897). 
