madreporite
noun
mad·re·por·ite ˈma-drə-ˌpȯr-ˌīt 
: a perforated or porous body that is situated at the distal end of the stone canal in echinoderms
Word History
Etymology
madrepore + -ite entry 1 (segment); from the resemblances of the perforations to those of a madrepore
First Known Use
1869, in the meaning defined above