The water vascular system is a hydraulic system used by echinoderms, such as sea stars and sea urchins, for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. Echinoderms move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.
The exact structure of the system varies somewhat between the six classes of echinoderm.
Read more about Water Vascular System: Sea Stars, Ophiuroids, Sea Urchins, Crinoids, Sea Cucumbers
Famous quotes containing the words water and/or system:
“The senseless drowned
Have faces nobody would care to see,
But water loves those gradual erasures
Of flesh and shoreline, greenery and glass,”
—Howard Moss (b. 1922)
“The violent illiteracies of the graffiti, the clenched silence of the adolescent, the nonsense cries from the stage-happening, are resolutely strategic. The insurgent and the freak-out have broken off discourse with a cultural system which they despise as a cruel, antiquated fraud. They will not bandy words with it. Accept, even momentarily, the conventions of literate linguistic exchange, and you are caught in the net of the old values, of the grammars that can condescend or enslave.”
—George Steiner (b. 1929)