Investigations of the capacity of synthesizing 3β-sterols in mollusca—VI. The biosynthesis and composition of 3β-sterols in the neogastropods Purpura lapillus and Murex brandaris

1. 1. It is shown that Purpura lapillus and Murex brandaris are capable of synthesizing sterols from mevalonate and acetate. The biosynthesis of sterols from acetate proceeds only at a slow rate. This phenomenon is compared with that observed in Natica cataena . 2. 2. The composition of the sterol mixtures of P. lapillus and M. brandaris is determined by means of gas-liquid chromatography. 3. 3. In both animals cholesterol is the principal sterol making up 77 and 59 per cent of the total sterols respectively. The sterol composition of Murex differs rather strongly from that of other prosobranchs.