Aboral surface.

Close up on the pair of posterior spines (longer).

Stage with three pairs of arms.

Larva with four pairs of arms.

Arm growing on an unusual site.

Skeleton and digestive cavity.

Aboral surface (opposite to mouth).

Stage with three pairs of arms.

Tip of antero-lateral arms.

Early stage with two arms (post-oral).

Oral region with the lantern of Aristotle in formation.

Lantern of Aristotle in the oral region.

Early with two arms.

Stage with three pairs of arms.

Oral region.

Anus in the aboral surface of the juvenile (red structure) and fecal pellets being released.

Oral region with the lantern of Aristotle in formation.

Extended archenteron.

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

Aboral surface.