ceratospongiae

from The Century Dictionary.

• In Claus's system of classification, the second order of the class Spongiæ; the horny sponges, for the most part branched or with massive sponge-stocks, with a framework of horny fibers in which grains of silex and sand are embedded. Also Keratospongiæ.

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

• noun plural (Zoöl.) An order of sponges in which the skeleton consists of horny fibers. It includes all the commercial sponges.