pleosponge
noun
ple·o·sponge
ˈplēəˌspənj
: any of various Lower and Middle Cambrian calcareous, cylindrical or cup-shaped, double-walled, porous fossils that may be the remains of sponges or primordial precursors of the true corals
Word History
Etymology
New Latin Pleospongia, from pleio- + -spongia