Assertion: glass sponge | /r/HasProperty | hydnoceras
Facets:
Source sentences:
text: The spicules can have any number of points; the fossils of the glass sponge Hydnoceras from the Devonian (390-360 mya) look for all the world like they're wrapped in plaid thanks to their six-pointed spicules which appear four-pointed in the two dimensions apparent on its exterior.