Detail of the stromboid notch in
Strombidae seashell (Strombus sp.). Image taken from the book Dr. Johannes Leunis Synopsis der thierkunde. Ein handbuch für höhere lehranstalten und für alle, welche sich wissenschaftlich mit der naturgeschichte der thiere beschäftigen wollen (1883); by Johannes Leunis and Hubert Ludwig.
The stromboid notch is an anatomical feature which is found in the
shell of one
taxonomic family of medium-sized to large sea snails, the
Marinegastropods in the family
Strombidae have a notch in the edge of the shell
aperture not far from the
siphonal canal. This indentation is called the stromboid notch. Its function is to enable the animal to extend one of its two stalked eyes out through the notch when the animal is active.
This Strombus alatus shows its
siphon in front and stalked eyes behind. The eye stalk on the left in the image is protruding through the stromboid notch.