spongiae

from The Century Dictionary.

• Sponges; the mesodermalian class of Cœlentera, having a branching canal-system (the organs of which are developed from cells of the mesogæa, or primary mesoderm), simple epithelia, endodermal collar-cells, and no cnidoblasts or movable appendages.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) The grand division of the animal kingdom which includes the sponges; -- called also Spongida, Spongiaria, Spongiozoa, and Porifera.