Assertion: sponge's spicule | /r/AtLocation | the demospongiae
Facets:
value: in the hexactinellida
type: LOCATION
Source sentences:
text: Siliceous spicules, found in the Demospongiae and in the Hexactinellida, are made essentially of silicic acid; they also contain some water, a small quantity of other compounds containing sodium, potassium, iron, and chlorine, and a small quantity of organic matter, called spiculin, which forms an axial fibre.