CIRCULATORY APPARATUS OF THE NEMERTBEA. 49 
which resembled a blood-vessel. Once a transverse vessel ran 
from it to the circumference of the intestine, but as the sec- 
tions were made only through the upper quarter of this 
region I cannot say anything more on the further course of 
this vessel. 
Somewhat on one side of the upper half of the intestine I 
saw a second longitudinal vessel, which is undoubtedly a 
nephridial canal. ; 
Over the intestinal diverticula transverse vessels run from 
the median vessel to the two ventral ones. Fig. 65 gives us 
a representation of a transverse section through such a transverse 
vessel, around which the surrounding stroma is radially 
folded, with numerous nuclei heaped in the immediate 
neighbourhood. 
9. Cerebratulus hepaticus, Hubr., fig. 66, 69, very similar 
to C. marginatus. 
In the head there are within the circular muscular layer 
three large lacunz (one above the proboscidian sheath), sepa- 
rated from one another by two massive bundles of longi- 
tudinal muscular fibres. In the region of the cerebrum the 
longitudinal fibres have increased in number, lying against the 
circular muscular coat. The proboscidian sheath, at first lying 
against the lower arch, has removed towards the upper arch of 
the circular coat. The lacune have united to one, which is 
horse-shoe shaped, with its legs upwards. The lacuna com- 
municates directly with the median vessel in the proboscidian 
sheath. Behind this section, some fibres of the circular layer 
of the proboscidian sheath to the left and to the right take 
their course downwards, very obliquely, however, so that they 
cross one another, and cut the horse-shoe shaped lacuna into 
three. The one lying beneath the proboscidian sheath is 
triangular with its top turned upwards. The circular muscular 
layer of the proboscidian sheath increases considerably, so that 
the lacunz are pressed sidewards, and the lower lacuna very 
far downwards. In the meanwhile the two lateral lacunz em- 
brace the posterior cerebral lobes, and the sides of the tri- 
4 
