544 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
leading to the exterior of the body. The vessels with which he 
thought the flame cells connected, and which he calls the nephridial 
tubules, must in reality have been blood vessels, for they have the 
same structure as the latter, with the same deeply staining gland 
cells, and were seen to open directly into the larger blood vessels. 
Dendy was thus led to the conclusion that the nephridia open 
directly into the blood vessels, a conclusion which has been pre¬ 
viously reached for a number of nemerteans, but one which has 
been found incorrect where detailed microscopic study of well pre¬ 
served material has been possible. 
In the anterior half of the esophageal region are a considerable 
number of very small efferent ducts, most of which pass beneath 
the lateral nerves to open on the ventro-lateral surfaces of the body. 
The actual number probably varies in different individuals, but in 
the specimens examined there were apparently at least fifteen on 
each side, although some of the ducts were so small as to be dis¬ 
tinguished with difficulty. 
Nervous system and sense organs. — The brain and lateral nerves 
present no marked deviations from the type characteristic of the 
Hoplonemertea. 
The cerebral sense organs are remarkably small, measuring in a 
worm of moderate size only 0.12 mm. in diameter, and therefore in 
transverse section but slightly larger than one of the ocelli. In spite 
of their small size, however, the cerebral sense organs exhibit the 
usual relations of ciliated canal, sensory portion, and glandular por¬ 
tion. They are situated in the ventral half of the head slightly 
anterior to the ventral ganglia. From the sensory portion of the 
sense organ the ciliated canal passes forward to open on the ventro¬ 
lateral surface of the head (fig. A), as in related species, while a 
slender, much coiled, glandular tube extends posteriorly as far as 
the anterior end of the ventral brain lobe. 
Especially remarkable is the presence of a pair of horizontal 
grooves leading from the proboscis pore back for soijie distance on 
the lateral margins of the head. These grooves occur in all indi¬ 
viduals after preservation and are conspicuous in transverse sections 
through the snout. They are lined with long columnar ciliated cells, 
and are evidently to be reckoned among the special sensory organs 
of the body, being strikingly similar to the horizontal cephalic fur¬ 
rows of the Heteronemertea. The external openings of the ciliated 
