rod-shaped gemmosclere of freshwater sponges with discs at both ends; the disc edges are mostly incised or frayed, but in some genera hey are smooth.
The same term is used for dumbell-shaped microscleres of Hexactinellida, with three size classes termed macramphidisc, mesamphidisc and micramphidisc.

Alternative forms for amphidisc : amphidisc, amphidiscs, amphidisks.