Abstract
The growth and activity of the coelomic cells of Sabella spallanzanii are described. Qualitative and quantitative determinations were made throughout the year of the glycogen, oil, and pigments which they contain. The coelomic cells accumulate carotenoids, including astaxanthin. The possibility of the interconversion of glycogen and oil by the cells is discussed, and it is concluded that the coelomic cells constitute a depot for the maturation of the gametes. This system is paralleled in some other sabellids by the development of a villous peritoneum. Such tissues contrast with the chloragogen tissue in that they have no direct contact with the blood vascular system.