Early stage with two arms (post-oral).

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

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

Frontal view of a two-arm pluteus larva.

Stage with three pairs of arms.

Early eight-arm stage, lateral view.

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

Ossicles of the lantern of Aristotle in formation at the oral region.

Stage with three pairs of arms.

Oral region.

Growth of antero-lateral pair of arms (2nd pair).

Stage with three pairs of arms.

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

Ossicles of the lantern of Aristotle in formation at the oral region.

Lateral view of mesomeres.

Early stage with two arms (post-oral).

Ossicles of the lantern of Aristotle in formation at the oral region.

Ossicles of the lantern of Aristotle in formation at the oral region.

Post-oral arm tip in a six-arm pluteus larva.

Tip of a post-oral arm.

Ova.

Arm growing on an unusual site.