Assertion: sponge's cell | /r/CapableOf | perform secrete crystalline spicules
Facets:
Source sentences:
text: The exterior of sponges is coated with epidermal cells; in the wall of the sponge are wandering amoeboid cells that perform some immune-system like duties and secrete crystalline spicules (usually calcium carbonate or silicic acid) or proteinaceous fibers that support the sponge; special cells called porocytes can encircle the inflowing wall pores; and distinctive choanocytes, or collared cells, line the interior spaces of the sponge.