The floating urchip has changed in such a way from its ancestor, that its way of locomotion has changed. Instead of following the currents, they simply zigzag to their designated location. They've also benefited from the going up and down while in crystal shrubite colonies. When going down, they're able to take a big gulp of them.
Their chambers are split using chitin-like substances, creating an excessive amount of chambers. This amount helps the floating urchip to control where they're going. Also, the chitin protects the eyes - when their eyes are closed, the bony chitin protects it.
To gain more young, their flanges have grown larger, to protect more young within.