Vermetus triquetrus is a species of sea snail, a marine gastropod mollusk in the family Vermetidae, the worm snails or worm shells.

It is known in the fossil records from the Jurassic to the Quaternary (age range: from 164.7 to 0.0 million years ago).

[2] These sea snails are characterized by an unusual appearance and lifecycle.

Later they fasten to a hard substrate using calcareous secretions, and the shell starts to take the form of an irregular tube.

[3][4] Vermetus triquetrus is widespread in the Mediterranean Sea and in the North Atlantic Ocean.