Abstract
The calcium oxalate dihydrate mineral, weddellite, has been identified in a microarchitectural component of the gizzard plates from the deepwater gastropod Scaphander cylindrellus. This is the first indication of nonpathologic precipitation of this mineral by an animal species. A new occurrence of weddellite in sediments from the Weddell Sea, Antarctica, is also reported, lending support to the earlier interpretation that the mineral is an authigenic constituent of the sediments in this area.