Larva with four pairs of arms.

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

Lantern of Aristotle in the oral region.

Aboral surface.

Spine and podia.

Stage with four pairs of arms.

Lantern of Aristotle.

Ring of mesenchyme cells beginning to secrete the calcareous skeleton.

Larval skeleton seen through polarized light.

Early eight-arm stage.

Early eight-arm stage.

Aboral surface (opposite to mouth).

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

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

Pair of coeloms developing next to the gut in a two-arm larva.

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

Stage with three pairs of arms and vestibule invagination on the left side.

Larva with six arms.

Accelerated 25x.

Larva with three pairs of arms.

Larva with four pairs of arms and coeloms extended along the gut.

Early stage with two arms, side view.

Larval skeleton with three pairs of arms.