the stone canal connects the madreporite to the ring canal and the ring canal allows water to flow into the radial canals, just tubes...

They connect the radial canal to the ampullae in the water vascular system.

that's easy it goes through the sieve plate, to the stone canal, then into the ring canal , to the radial canal and out the tube feet which are also used for respiration :)

The Illinois and Michigan canal connected Lake Michigan to the Mississippi River. It was used to transport grain, lumber, and stone.

Ken MacLeod has written:

'The stone canal'

'Dark light'