Most species are shaped like an elongated, stylized droplet, and are opaque white or yellow; they frequently have contrasting bands or spots in colors, such as purple, yellow, red, or brown.

They have no to three (normally two) pairs of pigment-cup eyes, and well-developed tactile and chemoreceptor senses.

Egg capsules are, according to species, glued to various hard surfaces; the young hatch as miniature copies of their parents.

Although most are accomplished swimmers, they normally rarely venture far from the bottom; young specimens are sometimes found in plankton.

This is probably due to a sampling artefact, as prolecithophorans are known to be common in the tropics; when Norén & Jondelius[3] sampled the shore adjacent to Phuket Marine Biological Center, Phuket, Thailand, they found 14 species of prolecithophorans, all of which were new to science.