Chondrilla nucida Schmidt is probably the most ubiquitous sponge of the shallow waters of the Bermuda Archipelago. Unlike most other common sponges it is very dense, and in shape, size, and color reminiscent of a chicken liver. The contents of fatty materials of this sponge are shown in Table I.The crude sterol obtained from Chondrilla was dextrorotatory and gave a positive Tortelli-Jaffé (1) reaction. It was at once benzoylated, and the benzoates were subjected to a series of fractional recrystallizations. There were eventually obtained two fractions, of which the least soluble, m.p. 195°, represented the benzoate of a sterol different from all other sterols which have so far been described. Since the sterol was first isolated from Chondrilla, it is proposed to name it chondrillasterol. The properties of this sterol and of some of its derivatives are shown in Table II.Titration with perbenzoic acid proved the sterol to be diunsaturated. Its