Hydroskeleton (S) High internal pressure maintained within the pseudocoelom, pushing outward on the cuticle, can give the nematode a significant structural integrity not unlike the solid skeleton in higher animals. In fact, C. elegans is known to be able to leave the substrate and actively wave its body in the air (nictation), holding fast just by its tail.

a water-based skeleton present in many animals (such as the earthworm) that lack structures, such as bone, for muscles to pull against.

( hy-droh- stat-ik) A skeletal system composed of fluid held under pressure in a closed body compartment; the main skeleton of most cnidarians, flatworms, nematodes, and annelids.

A fluid skeleton in many soft-bodied invertebrates, including annelids, that allows an organism to change shape but not volume.

Fluid-Þlled closed chambers that give support and shape to the body in organisms such as jellyÞsh and earthworms. No to be confused with the water-vascular system of echinoderms.

The incompressible internal liquids of some animals that transfer forces from one part of the body to another when acted upon by the surrounding muscles.

A hydrostatic skeleton or hydroskeleton is a structure found in many soft-bodied invertebrates consisting of a fluid-filled cavity, the coelom, surrounded by muscles. The pressure of the fluid and action of the surrounding muscles are used to change an organism's shape and produce movement, such as burrowing or swimming. Hydrostatic skeletons have a role in the locomotion of echinoderms (starfish, sea urchins), cnidarians (jellyfish), annelids (earthworms), nematodes, and other invertebrates.