Bathycrinus aldrichianus is a species of sea lily, a crinoid in the family Bathycrinidae. It is native to deep water in the North Atlantic Ocean. It was first described by the Scottish marine zoologist Charles Wyville Thomson (who had been chief scientist on the Challenger Expedition) and named in honour of Pelham Aldrich, a British naval officer and explorer. It is believed to be the crinoid living at the greatest depth.