Bipinnaria

Starfish that brood their young generally lack a bipinnaria stage, with the eggs developing directly into miniature adults.

A pair of short, stubby arms soon develop on the body, with the ciliated bands extending into them.

In addition to propelling the larva through the water, the cilia also catch suspended food particles, and deliver them to the mouth (more correctly called a stomodeum).

In some species, including the common starfish Asterias, the bipinnaria develops directly into an adult.

It is very similar in appearance to the tornaria larvae of some Hemichordata, reflecting the descent of the Ambulacraria from a common ancestor.