Hyalospongia \Hy`a*lo*spon"gi*a\, n. pl. [NL., fr. Gr. "y`alos glass + ? a sponge.] (Zool.) An order of vitreous sponges, having glassy six-rayed, siliceous spicules; -- called also {{Hexactinellin[ae]}}. [1913 Webster]