28 A. ©. OUDEMANS. 
wall of the canal itself. Its cells have a typical glandular 
structure and design. A transverse section through the 
nephridial canal shows, in regard to the form and habitus of the 
cells (without their cilia), a perfect resemblance to all glandular 
ducts or glands of the stomach or other glands. The nephridial 
canal has more the appearance of a blood-vessel, with the same 
histological structure as the blood-vessel lying next to it, 
and thus probably serves as a reservoir for the materials 
excreted from the blood by the nephridial gland. In Cari- 
nella, cilia were absent; but a circular muscle layer sur- 
rounded the nephridial canal. In Carinoma, cilia are 
present, even in the extremity of the excretory duct; but the 
layer of circular muscular fibres is absent. All the cilia are 
directed outwards. In Carinoma, too, the excretory duct 
has the appearance of having progressed outwards, for the 
basal membrane, and even a small part of the circular muscular 
layer inside of it, are pressed outwards, as in Carinella. As 
far as close to the surface the duct is invested with its epi- 
thelium, and only at the rim of the opening there are cells that 
are intermediate between skin epithelium cells and nephridium 
glandular cells. Thus, the structure indicates that the nephridial 
system of Carinoma has a higher development than that of 
Carinella. 
I have examined only a few sections behind this region, the 
body being still several centimetres longer. The blood-vessels 
do not show anything peculiar. In the tail their communica- 
tion is very peculiar. They can indeed be followed till nearly to 
the tip of the tail, where, however, they do not coalesce directly 
but gradually increase in size, becoming lacune which com- 
municate above the proctodeum. But anteriorly to this 
connection already many lacunz, for the most part also above 
the intestine have become visible, which communicate from 
time to time with the vessels themselves, forming thus rudi- 
mentary transverse contracting vessels! It is very probable 
‘that these lacune also communicate with one another. 
Laterally to the vessels I have also seen lacunar spaces, but I 
could not find any communication, either with the vessels, or 
