MONILIGASTER GRANDIS, A.G. B. 337 
NEPHRIDIA. 
There is in Moniligaster grandis a pair of large ne- 
phridia in each segment except Segments 1 and 11 and (at 
any rate in the worm from which I cut sections of the anal 
end of the body) the two most posterior segments. 
The nephridium consists of (1) a nephrostome or funnel 
which, with a small portion of the duct, is preseptal, (2) the 
nephrostomial duct passing from this to (3) the glandular lobe, 
(4) the vesicle duct leading to (5) the large vesicle, and (6) the 
terminal duct leading to the nephridiopore. Regions 2—6 are 
post-septal. 
The general relations of these regions are shown in fig. 42. 
On the outside of the greater part of the nephridium there is 
a layer of connective tissue (fibrous, not vesicular), and outside 
this, again, a layer of coelomic epithelium cells.! There is a 
continuous lumen passing from the nephrostome to the 
nephridiopore which is intra-cellular, at any rate as far as the 
entrance to the vesicle, and possibly even in the vesicle and ter- 
minal duct. 
The lumen consists of the following regions :—(“S¢. a”) A 
narrow ciliated tube leading from the nephrostome to the 
glandular lobe; here it communicates with (‘‘ab”’) a branch- 
ing system of ductules, the cells pierced by which lie on the 
outside of the first third of the glandular lobe; these branch- 
ing ductules collect into a narrow duct (“‘dc” and “cd”), which 
passes on to the apex of the glandular lobe and returns upon 
itself and passes right back to the first bend of the glandular 
lobe. Where there are two portions of this narrow duct 
running side by side (as there are in the distal two thirds of 
the glandular lobe), there are transverse ducts every here and 
there placing one of these limbs of the narrow duct in com- 
munication with the other (fully shown in the figure in a little 
1 These cells, as may be proved by the careful use of silver nitrate, occur 
on the wall of the vesicle, as well as elsewhere. 
