(in an echinoderm) a network of water vessels in the body, the tube feet being operated by hydraulic pressure within the vessels.
- ‘Like all echinoderms, echinoids are pentaradially symmetrical, have a water-vascular system, and have an internal skeleton made of calcitic ossicles (plates).’
- ‘In starfish, only the left hydrocoel of the larva develops into the adult water-vascular system, while the right hydrocoel disappears.’
- ‘These tube feet are extended and retracted by hydraulic pressure in the water-vascular system.’
- ‘However, Arkarua lacks a stereom or any sign of a water-vascular system.’
We take a look at several popular, though confusing, punctuation marks.