Podia and spine.

Female

Epithelial cells with pigmented granules during growth of antero-lateral arms (2nd pair).

Early vestibule invagination in a six-arm stage.

Denominadas pelagosferas, as larvas de muitas espécies de sipuncúlidos são transparentes e nadam livres na água por meses antes de se transformarem no adulto, que tem aspecto vermiforme e vive enterrado na areia ou lodo.

Larval pre-oral arms on a eight-arm pluteus.

Lateral view. Detail of the lantern of Aristotle under the peristomial membrane (where mouth will open).

Stage with four pairs of arms.

Newly released medusa.