STUDIES ON EARTHWORMS. 289 
vesicle, are surrounded by a loose connective tissue whose large 
cells have definite boundaries (Pl. XVI dis, fig. 32); imme- 
diately round the “drain-pipe” cell of the lumen is some 
fibrous connective tissue, whose flat nuclei are shown in fig. 32 ; 
this forms a “sheath” (ct’) to the main lumen, though I have 
not found it farther away from the vesicle. Outside this sheath 
is the looser connective tissue. In this region only the main lu- 
mina exist. But farther away from the vesicle the “ secondary” 
and “smaller lumina” commence (fig. 33), the whole set of 
lumina, forming one limb of a loop, is surrounded by a granular 
connective tissue whose limits are not well defined. Nuclei are 
scattered about, and blood-vessels are seen cut through in a 
section; but whether these blood-vessels actually pierce the 
nephridial cells, or pass between them, I am unable to say. 
Round the short lumen leading through the septum to the 
funnel is a looser connective tissue like that near the vesicle. 
The course and communication of the various lumina I have 
not as yet followed out. Whether only one “ main lumen,” or 
whether several communicate with the vesicle, I am likewise as 
yet uncertain, as also whence the lumen to the funnel springs. 
(8) The internal opening (ne.f.) (Pl. XVI, fig. 22) lies in 
the somite preceding that in which the tubules are placed. A 
narrow duct leads through the septum, and having passed this, 
the connective tissue round it assumes a looser form, and is 
lobed ; the internal opening does not present itself in the form 
of an expanded funnel as in Lumbricus; it may be easily over- 
looked, as it is very small. The cilia (Pl. XVI, figs. 22, 23, 24) 
at the internal opening are very long, and are continued for some 
distance down the lumen ; how far they actually extend I am 
unable to say, but as I could see none in the tubules of the 
rosette they are probably confined to the lumen leading to the 
funnel. 
The shape of the vesicle varies somewhat in different regions 
of the body; that described above is one from the posterior 
region, In somites 11 and 111 it is very much elongated; the 
anterior extremity ends in the external pore, whilst posteriorly 
it enlarges and gives off the tubules, which are there situated 
