FEEDING HABITS OF NEREIS VIRENS, SARS 431 
consistent responses to food of any kind. They fed freely upon 
sea lettuce and other plants placed in the aquaria, but the find- 
ing of it was more or less accidental. Food hidden in sand, 
placed in cheese-cloth bags, or otherwise concealed was, as far 
as could be determined, never detected by the worms. Ani- 
mals from which one or all of the pairs of cephalic appendages, 
such as the tentacular cirri, palps, and tentacles, were removed, 
fed and thrived as well as normal animals. 
It is evident that the sense of taste, or chemical sense, of 
Nereis virens does not play an important role in locating and 
selecting food. It is conceivable, however, that a chemical 
sense may be developed which enables the worm to detect certain 
unfavorable environmental conditions of the water and mud in 
which it hves. 
To test the chemotropism of Nereis, simple reagents, such as 
HCl, KOH, NaOH, KCl, NaCl, and NH4CI, were used. The 
worms were tested by the various methods used by Parker, 
Hurwitz, Shohl, Crozier, and Irwin, on the earthworm. The 
fence method used by Shohl proved to be the most satisfactory 
for the experiments on Nereis. For this purpose a rectangular, 
shallow glass tray w^as divided into two compartments by a paraffin 
partition, a quarter of an inch wide. A notch about three-quar- 
ters of an inch long and reaching within a hah inch of the bot- 
tom, was cut in the middle of the partition. The entire tray 
was covered over with a thin layer of paraffin, to prevent the 
fiquids from wetting the walls. Sea-water was placed on one 
side of the fence and sea-water containing the stimulating sub- 
stance on the other side. The worms were transferred from the 
individual dishes in which they were kept to the notch in the 
fence by means of two paraffin-covered wooden spatulas. The 
worms thus placed were free to crawl into the hquid toward 
which their anterior end was directed or to withdraw into that 
on the opposite side of the fence. Nereis was found to be very 
strongly negatively chemotrophic to all the reagents used. The 
reaction times of the worms, which increased inversely as the 
strength of the stimulating substances, were recorded by means 
of a stop-watch controlled by foot pressure. 
