CIRCULATORY APPARATUS OF THE NEMERTEA. 15 
phridial system. Hubrecht mentions (35) in the living animal on 
the level of the mouth a lateral opening, and adds (“of the 
water-vascular system ?”): I can only mention that the blood 
spaces, seen on transverse section, here send a diverticulum 
towards the periphery above the lateral nerves. But I have 
never seen an opening, nor anything that could represent a 
nephridial system, such as I shall describe below in Carinella. 
2. Carinella annulata (Mont.), McInt., figs. 2, 4, 19—27. 
The vascular system consists chiefly of two longitudinal 
vessels, which communicate in the tip of the snout and in the 
tail. I have not verified the presence of this last-named com- 
munication. Two longitudinal vessels in the proboscidean 
sheath, never, however, extending any further than the cesopha- 
geal region, are perhaps only of secondary importance. I 
will henceforth call the individuals which are deprived of 
these vessels those of the first form, the others I will designate 
as the second form. (See the Explanation of the Plates.) 
In the head we find two great lacunar spaces, one on each 
side of the probiscidian sheath (fig. 19). They fill up the 
head—before the ganglia—and have the proboscidian sheath 
between them. Besides these two lateral lacunz one some- 
times finds (not, however, seen by me in all the specimens) a 
broad and flattened lacuna above the proboscidian sheath, 
which has the whole width of the proboscidian sheath, but is 
tolerably flat in transverse sections, and which is temporarily 
separated from the other lacunz by transverse muscular bands. 
In the tip of the snout the two lateral lacunze communicate by 
an arch above the proboscidian sheath. When the lacune 
above the proboscidian sheath is present, it also opens in the 
above-mentioned arch. Further backwards this process is 
repeated just behind the supra-proboscidian commissure, and 
in front of the infra-proboscidian one. A broad arch is here 
situated above the proboscidian sheath. But between the two 
arches the lacuna above the proboscidian sheath has already 
had occasion here and there to mix its fluid contents with that 
