212 MANTON COPELAND 
the implement used in removing the more inaccessible parts. 
Nine animals were operated upon and their subsequent behavior 
recorded. From four of them, however, no final conclusions 
could be drawn. One had its mantle and siphon so badly con- 
tracted that it could not be satisfactorily studied. There was a 
large hole through the mantle. Another, which failed in several 
trials to follow oyster extract, or to extend its proboscis, al- 
though exhibiting but slight contraction, appeared sluggish and 
the mantle proved to be punctured. The third snail developed 
serious contraction of the siphon, so that it could not be ade- 
quately experimented upon, and again holes were found in the 
mantle. The first time it was tested with the extract it ex- 
tended its proboscis and ate a piece of oyster, and at another time 
contracted its foot and toppled over. In this position it thrust 
out its proboscis and then took a piece of oyster. The protrusion 
of the proboscis in the latter instance was very questionably 
the result of chemical stimulation, and in the former one, the 
juices may have been concentrated enough to have effectively 
stimulated the skin receptors, for the animal was resting. No 
locomotion was induced by the oyster extract, and when buried 
in the sand the snail failed to respond to it, although it did so 
actively before the operation. The fourth animal was one which 
had shown normal scenting reactions after the osphradium 
had been partly singed with a heated platinum wire. After 
scraping away the osphradium, there was no response such as 
occurred before. In one instance, when the snail was resting | 
against the corner of the aquarium with its foot contracted and 
its siphon directed upward, the application of oyster juice was 
followed by an extension of the proboscis, but no locomotion. 
The position of the snail was such that the stimulating material 
probably collected over the rhynchostome region and caused the 
reaction. Abnormal behavior and contraction of the siphon 
led to an inspection of the mantle where the osphradium had 
been removed and, as was expected, a hole was found. The 
view that the ill effects of the operations seen in these and certain 
other snails were due to puncturing the mantles, which allowed 
water to pass behind them, rather than to the removal of the 
