Hyolithelmintida

Hyolithohelminths are phosphatic tubular fossils from the Cambrian period. They were sedentary, possibly infanual, organisms; once thought to have opercular (hence the comparison with hyoliths), these structures are now understood to be unrelated shells.

Hyolithelmintida

Hyolithohelminths are phosphatic tubular fossils from the Cambrian period. They were sedentary, possibly infanual, organisms; once thought to have opercular (hence the comparison with hyoliths), these structures are now understood to be unrelated shells.