madreporite

noun

1. A calcareous opening in the body of echinoderms which connects the water vascular system to the environment.
2. (archaic)A fossil stony coral, or a deposit composed of the same.

   “a similar Madreporite deposite is noticed a few feet above the coal seam”

   “Whether madreporite occurs naturally in Spain, I do not know”

   “Madreporite was regarded as a variety of calcite and anthraconite a lamellar variety of madreporite”