Siphonal canal

A shell of Penion cuvieranus cuvieranus, with the long siphonal canal visible extending toward the bottom of the image, at the anterior end of the shell.

Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In many carnivorous snails, where the siphon is particularly long, the structure of the shell has been modified in order to house and protect the soft structure of the siphon. Thus the siphonal canal is a semi-tubular extension of the aperture of the shell through which the siphon is extended when the animal is active.

One gastropod whose shell has an exceptionally long siphonal canal is the Venus comb murex. Some gastropods have a simple siphonal notch at the edge of the aperture instead.

See also

• siphonal notch
• stromboid notch

Further reading

• Vermeij G. J. (2007) "The ecology of invasion: acquisition and loss of the siphonal canal in gastropods". Paleobiology 33(3): 469-493. doi:10.1666/06061.1.