stereoplasm

from The Century Dictionary.

• noun The denser or more solid portion of the protoplasm of the cell, as distinguished from the more fluid portion, or hygroplasm.
• noun In corals, a delicate endothecal structure occupying different positions in the corallite, often forming vertical processes in the interseptal loculi or encircling septa, or acting as true endotheca.
• noun In botany, same as stereoplasma.

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

• noun (Biol.) The solid or insoluble portion of the cell protoplasm. See hygroplasm.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun biology The solid or insoluble portion of the cell protoplasm.