FEEDING HABITS OF NEREIS VIRENS, SARS 433 
correlated with the high percentage of NaCl and the low per- 
centage of KCl in the sea-water to which Nereis is adapted. 
The author hopes to perform experiments on this interesting 
and important aspect of the problem which involves the rela- 
tions of osmotic pressure and sense of taste to the stimulating 
substances used as well as the relative stimulating efficiency of 
the various reagents. 
This paper involves only those experiments made on Nereis 
in an effort to determine whether the chemical sense is localized 
in certain cephalic appendages or in other parts of the worm. 
For a preliminary test twenty-four worms of a uniform size 
(10 to 12 cm. long) were numbered and placed in separate finger- 
bowls, each containing 20 to 25 cc. of sea-water and a small 
piece of sea lettuce. The latter aerated the water and provided 
food for the worm. Each individual of the whole series of Nereis 
was given one test in its turn with the HCl, then one test with 
the KOH, and so on until the entire set of readings for each of 
the two reagents was obtained. The order of the worms in the 
test was reversed each time a new series of readings was taken. 
All the experiments were made under conditions controlled for 
temperature and light, and, as far as possible, free from mechan- 
ical stimulation. After each individual test, the worm was 
rinsed in fresh sea-water before being returned to its bowl. The 
sea-water containing the stimulating substance, as well as the 
plain sea-water, was renewed after each set of readings, since a 
small amount of the liquid was carried from one side to the other 
by the worm. 
After the reaction time of the worms had been determined, 
the tentacular cirri, palps, and tentacles of the first twelve of 
the twenty-four Nereis were removed, while the other twelve of 
the series were retained in a normal condition to be used as a 
control. The entire series was left undisturbed for a period of 
six days, a length of time more than sufficient for the wounds 
made by the operations to heal. Readings were then made as 
before to determine what effect, if any, the removal of the 
cephalic appendages had on the sensitiveness of the worms to 
chemical stimulation. 
