4.44, WILLIAM NICOLL. 
is well developed.. The fibres of the cesophagus are stouter 
and more elosely set than those of the diverticula. They 
have a diameter of about :0015 mm., and are separated by 
about the same distance or slightly more in the case of the 
longitudinal fibres. Those of the diverticula measure 
‘0004 mm. with spaces of (0055 mm. in the case of the annular 
fibres, and ‘0075 mm. in the case of the longitudinal fibres. 
These figures of course are only approximate, for there is 
great variation with the state of contraction. A moderate 
number of circum-cesophageal cells (myoblasts) are present. 
The excretory system is of simple type. There is a small 
undivided vesicle not extending further forward than the 
anterior testis and opening by a pore at the posterior end of 
the body. From the vesicle two narrow, transversely oval, 
collecting tubes are given off. They pass outwards to lie close 
to the outer side of the intestinal diverticula. Their course 
thereafter was not followed. 
The testes are two transversely-oval bodies of rather 
irregular outline lying midway between the ventral sucker 
and the posterior end of the body. ‘They are very close 
together, practically contiguous, and very often somewhat 
obliquely set, one behind the other. The anterior testis is 
displaced to the left side, while the posterior is nearly median 
or a little to the right. In many specimens they were found 
directly tandem, but no other difference could be found in 
those specimens, so they are probably only a variety. The 
testes are very nearly equal in size, the posterior being, if 
anything, a little larger. The long diameter measures 
31-387 mm., the short diameter ‘19-22 mm. The vasa 
deferentia arise from their anterior surface and pass forwards 
ventral to the shell-gland complex as two almost straight 
lines towards the vesicula seminalis. 
The cirrus-pouch (fig. 11) is of no great size, but it appears 
shorter than it actually is, owing to the backward displace- 
ment of the ventral sucker. It extends only a short distance 
beyond the anterior border of the sucker. Its total length is 
about ‘4 mm. he narrow anterior part, which has a terminal 
