(Don't mind me: speaking to myself again...
) They are related to Eltanin antennae...?
P.S. Just to clarify: the author of the reply above involving a connection with the "Eltanin antenna" does NOT share the view that said object is a sponge.
(Here is a succinct rundown of the available theories on its origins.)
[edit on 19-5-2008 by Vanitas]

