siliceous sponge
Technical term in biology for sponges with siliceous spicules, i.e., all sponges except those of class Calcarea.
Siliceous sponge is used as a general term for sponges other than those of the class Calcarea.
Refers specifically to calcareous sponges (class Calcarea), which have calcium carbonate spicules, in contrast to siliceous sponges.
Compound of 珪質 (keishitsu, 'siliceous') and 海綿 (kaimen, 'sponge'). The exact historical derivation is uncertain; the term is a modern scientific coinage.