Found in all the oceans of the world, including the Arctic Ocean, appendicularians tend to remain near the water's surface where the density of phytoplankton is greatest.

Staining of a thin sliver of each block can highlight the main bodies of nerve cells (top, purplish image) with the darker areas indicating high cell density near the brain's surface.

The density of crystal defects in the region near the crystal surface is greater than that in the center.