OLFACTORY REACTIONS OF MARINE SNAILS 195 
Busycon, like the mud snail, has the habit of burying itself 
in the sand. When placed in an aquarium provided with a 
sandy bottom, it may enter it immediately, or in other cases 
after a time. <A portion of the shell may remain exposed, but 
more often the snail goes deep into the sand so that only the tip 
of the pallial siphon is visible above the surface. 
The response of a buried Busycon to food particles has been 
described by Colton (’08) as follows: 
The Sycotypus had not been fed for a month or so and was buried 
in the gravel. To stimulate, I added some very finely chopped-up 
oyster to the aquarium. When it started to crawl out of the gravel, 
a few minutes after I added the oyster juice, I placed some live oysters 
in the aquarium with it. It attacked one of the oysters five minutes 
after I placed them with it. 
Buried snails were stimulated many times by squirting oyster 
extract over the exposed siphon tip, and often the animal re- 
sponded by emerging completely from the sand after the manner 
of the mud snail. Sea water applied in the same way usually 
had no effect whatsoever, the most marked response noted being 
a contraction of the end of the siphon. In no instance did the 
snail come out of the sand. The usual reaction to oyster Juice 
was first a flaring and stretching upward of the end of the pallial 
siphon, followed by a lifting of the shell siphon and the final 
emergence of the rest of the body. Protrusion of the proboscis 
often occurred. 
The following test illustrates the reaction well, although it 
was a slow one: The snail was buried so that only the top of the 
shell and the siphon tip were visible. The latter was in contact 
with the glass side of the aquarium. Oyster extract squirted 
over the end of the siphon after a time caused, first this organ 
and the shell covering it to be lifted, and later the snail to come 
out of the sand. It then began to crawl up the side of the 
aquarium, where the juice had been applied, with its proboscis 
slightly extended. It was thrust out farther after more extract 
was taken into the siphon, and upon stopping the application 
of the substance, the snail ceased moving and worked its pro- 
boscis over the glass. It could not be made to crawl farther 
