The Hand Of Dusk Tapestry

Although the external morphology of these crinoids has not altered that much upon their adaptation to space, internally they are extremely different to their marine ancestors. To start with, the hydrostatic water vascular system has been largely replaced with the haemal system, although a remnant of the system is still used to operate the tube feet in the arms. They still don’t have a heart though, so the nutrient containing fluid in the haemal system is pumped around the body by the constant swaying of the stalk, which makes them look as if they are being moved by non-existent currents.