The spiny brittle stars are distant relatives of the
starfish and are found in intertidal zones (in tidal pools) up to 2000 metres
deep (they are very common close to giant kelps). They have got a central disk
clearly separated from their long and flexible arms, which, in this species'
case, are covered with long and erectile spines.
They possess 5 -rayed symmetry, mostly radial,
sometimes bilateral. Tubed feet.
Respiration consists of the water-vasculature system. This generally has one madreporite, which unlike sea stars is not on the surface. The water-vascular system enters into the madreporite and sieve plate, passes through the stone canal, and then traces a path from the ring canal encircling the mouth out to the five arms and then back out.
Respiration consists of the water-vasculature system. This generally has one madreporite, which unlike sea stars is not on the surface. The water-vascular system enters into the madreporite and sieve plate, passes through the stone canal, and then traces a path from the ring canal encircling the mouth out to the five arms and then back out.