Glia ( Virchow, 1846 ) : The so-called supporting cells (Hooke, 1665) of the nervous system (Monro, 1783) that are divided into four major embryonic lineages: astrocytes (including ependymal cells), oligodendrocytes, Schwann cells, and microglia. Virchow is usually given credit for discovering and naming glia (1846, pp. 247-248; also see Virchow, 1856).