Stage with three pairs of arms.

Detail of the mesenchymal cells secreting the larval skeleton on an early pluteus stage.

Anus on the juvenile aboral surface (red curved structure).

Larva with four pairs of arms.

Aboral surface (opposite to mouth).

Aboral surface (opposite to mouth).

Stage with four pairs of arms.

Aboral surface (opposite to mouth).

Stage with three pairs of arms.

Stage with four pairs of arms.

Oral region with the lantern of Aristotle in formation.

Larval epithelium during the growth of the antero-lateral arms (2nd pair).

Early stage with two arms (post-oral).

Stage with three pairs of arms.

View of the animal pole.

Structure in the anal region.

Non-fenestrated skeleton of antero-lateral arms.

Regression of larval tissues. Spicules of the larval skeleton are still present in the aboral region.

Early with two arms.

Aboral surface (opposite to mouth).

Blastopore and ring of mesenchyme cells secreting the larval skeleton.

Anal region of the larva with six arms.

Larva with three pairs of arms.

Stage with three pairs of arms.