The arms start to form and tube feet begin to appear.

Almost all species in this order have five arms with tube feet.

By day seven they have two pairs of tube feet and begin to move around.

Inside the mouth edge there is a second pair of tube feet.

Exchange of gases also takes place through the tube feet.

The animal handles the world outside by using its tube feet.

Highly modified tube feet around the mouth are always present.

Small organic particles are moved into the mouth by the tube feet.

The tube feet are pointed and do not have suckers.

The vessels of the water vascular system end in tube feet.

There are three rows of tube feet on the underside.

On the underside it has several rows of short tube feet.

The tube feet have no suckers, but instead end with a blunt point.

Tube feet allow these different types of animals to stick to the ocean floor and move very slowly.

Rows of tube feet are on the underside, and it has a central mouth.

It uses its tube feet to move across the surface or adhere to rocks.

The spines and tube feet enable the animal to move across the ground.

Their tube feet developed suckers, perhaps originally to improve movement.

Tube feet are moved by a water vascular system.

If the prey is too large to be swallowed whole, then it can use its tube feet to open shells.

The tentacles are usually the first adult features to appear, before the regular tube feet.

On the underside there are tube feet but these have no suckers.

On the underside there are multiple rows of tube feet running down each arm.

Like other members of its genus, it has tube feet without suckers.

In late stage larvae, tube feet may be seen developing round the skeleton.