No. 420.] HISTORY OF STICHOSTEMMA. 985 
nemertean the free portion made active movements. The nemer- 
tean was comparatively quiet, but at short intervals the mouth 
was widely opened and the body extended, and in this manner the 
Nais was drawn further into the alimentary canal. It could be 
clearly seen through the body wall of the nemertean that diges- 
tion of the annelid was proceeding very rapidly. Later a part of 
the Nais was disgorged, and some portions were seen to be com- 
pletely disintegrated, while others which had been in the ali- 
mentary canal only a few minutes, ten to fifteen, showed distinct 
evidences of digestion. This rapid digestion of the food was 
also observed by Wilson ('00) in the case of Cerebratulus. 
It appears extremely probable that the food is captured in 
the manner which Wilson (00) has described for Cerebratulus, 
though I have never observed it. Indeed, there is a striking 
similarity between this form and Cerebratulus, both in the 
nature of the food and in the method of taking it. In the 
cases of both an actively moving annelid forms the food, being 
attacked and overpowered by the nemertean, and in both 
cases the prey is often as large as its captor and always more 
active. I have not been able to determine whether Sticho- 
stemma always begins the process of swallowing at the posterior 
end of the body of its prey. In the one case of feeding actu- 
ally observed, the head of the naid had been broken off com- 
pletely and lay in the slime secreted by the nemertean, but 
the free end of the annelid was apparently the anterior end 
from which the head had been broken. In the bodies of the 
naids which had been completely swallowed digestion had 
always proceeded so far that it was impossible to determine 
with certainty which was the anterior end. 
The feeding apparently takes place only in darkness, or 
in light of little intensity, and therefore occurs normally 
during the night. During the day the nemerteans may 
remain in direct contact with the naids in the interstices of 
the masses of algae, but apparently do not attack them. The 
next day, however, or after a few hours in darkness, the naids 
are fewer in numbers and the intestines of the nemerteans 
indicate very distinctly a recent meal. The failure to observe 
the actual capture and, in all but the one case mentioned above, 
