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

Oral region with the lantern of Aristotle in formation.

Lantern of Aristotle in the oral region.

Aboral surface (opposite to mouth).

Structure in the anal region.

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.

Oral region.

Lantern of Aristotle in the oral region.

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.

Oral region.

Oral region.

Aboral region (normal position).

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.

Aboral surface (opposite to mouth).

Lantern of Aristotle in the oral region.

Aboral surface (opposite to mouth).

Aboral region (normal position).

Lantern of Aristotle.

Primary spine.

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

Remnants of the larval skeleton in the aboral region of the juvenile.

Lantern of Aristotle.

Oral region.

Close up of lateral spines.

Oral region.

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.

Lateral view.

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.

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

Aboral region showing the skeleton (sterom).

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.

Polarized light highlights the calcareous skeleton showing the structure of spines, podia, and remnants of the larval skeleton.