24 A. 0. OUDEMANS. 
the uppermost portion, which is bent outwards, is suddenly 
separated from the lacune by a portion of the gelatinous 
stroma that everywhere fills up the spaces between the different 
organs in the body of the Nemerteans (figs. 31 and 59). Thus 
there are now formed four lacunar spaces. McIntosh has not 
seen this connection between the four blood-spaces. These 
two supra-proboscidian sheath-vessels soon obtain a distinct hya- 
line basal layer and an epithelium (fig. 73), and extend to the 
nephridial region, where they terminate blindly. I have seen 
no other communications with the blood-vessels of these two 
supra-proboscidian sheath-vessels. 
Though they were very variable, and appeared to be subject 
to immense dilatation or contraction, they had, besides the two 
layers noted, no third layer of circular or longitudinal fibres. 
Their situation through the whole cesophageal region was the 
same laterally above the proboscidian sheath. Once I saw 
the left vessel extraordinarily dilated; once the right one 
divided into two, but sixty slices further these again merged 
into one (figs. 72 and 73). The blind end appears gradually, 
not abruptly. 
We have seen that in Carinella there is a tendency in the 
cesophageal region of the longitudinal blood-spaces to give off 
arch-shaped portions directed upwards. If we suppose a similar 
separation to have taken place along the whole length of the 
vessel in the cesophageal region, then we have the two supra- 
proboscidian-sheath-vessels of the genus Carinoma. (Com- 
pare the fig. 4 with 5, and 24 with 32.) 
In the same vertical section, where the two supra-probos- 
cidian-sheath-vessels spring from the two great lacune, I saw 
very clearly on the left side—on the right side only a tendency 
to it was visible—how the left vessel in the proboscidian sheath 
communicates with the lacuna. I have therefore exactly 
figured the left half in figs. 583—61 of four subsequent slices. 
Let us now call to mind for a moment what I have men- 
tioned, with due reserve, of what I have seen in the second 
specimens of the second form (see p. 18), and let us then 
compare fig. 59. The band of transverse fibres, which sepa- 
