Stage with four pairs of arms.

Ova.

Intermediate stage between gastrulation and pluteus larva formation.

Oral region with the lantern of Aristotle in formation.

Stage with three pairs of arms.

Early with two arms.

Lateral view.

Intermediate stage between gastrulation and pluteus larva formation.

Stage with three pairs of arms.

Larva with four pairs of arms.

Early stage with two arms (post-oral).

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

Spines.

Larva with four pairs of arms.

Muscles of the esophagus.

Early with two arms.

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

Oral region with the lantern of Aristotle in formation.

Vestibule in an eight-arm pluteus larva.