noun
calcareous sponge
Scientific term for any sponge of the class Calcarea, characterized by calcium carbonate spicules.
石灰海綿は炭酸カルシウムの骨片を持つ海綿動物の一群です。
Calcareous sponges are a group of sponges that have calcium carbonate spicules.
Compound of 石灰 (sekkai, 'lime, calcium carbonate') and 海綿 (kaimen, 'sponge'), referring to the calcareous nature of these sponges.