Triterpenoidal oligoglycosides contained in the Cuvierian tubules of the Bahamean sea cucumber Actinopyga agassizi SELENKA were shown to consist of a new lanostane-type triterpene tetraglycoside sulfate (24-dehydroechinoside A) (10) and holothurin A (11) in an approximate ratio of 2 : 1. The chemical structure of 24-dehydroechinoside A (10) was elucidated on the basis of chemical and physicochemical evidence.