Note: It has a large air sac, or float, with a sail-like
crest on its upper side. Numerous zooids of different
kinds are attached to the under side of the float. Some
of the zooids have very long tentacles; some have a
mouth and digest food; others produce gonophores. The
American species ({Physalia arethusa}) is brilliantly
colored, the float being pink or purple, and bright
blue; the zooids blue. It is noted for its virulent
stinging powers, as well as for its beautiful colors,
graceful motions, and its ability to sail to windward.