Eight-cell stage.

Larva with four pairs of arms.

Spines.

Stage with four pairs of arms.

Zygote.

Frontal view of the eight-arm pluteus larva.

Lantern of Aristotle in the oral region.

Early eight-arm stage.

Early eight-arm stage.

Four-cell stage.

Oral region with the lantern of Aristotle in formation.

Oral region.

Tip of antero-lateral arms.

Larva with six arms.

Accelerated 3x.

Larva with two pairs of aarms and early development of postero-dorsal arms on the body sides.

Found during an artificial fertilization experiment. We do not know if it is the result of abnormal development or if the larva was reproducing asexually.

Larva with six arms.

Found during an artificial fertilization experiment. We do not know if it is the result of abnormal development or if the larva was reproducing asexually.

Aboral surface.

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

Sphaeridia and spines.

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

Early stage with two arms (post-oral).

Aboral surface (opposite to mouth).