A new coccolithophorid, Crystallolitkus hyalinus, was described with the help of electron micrographs by Gaarder & Markali in 1956 from preserved material in which the cells lacked the appendages. From temporary cultures set up from our September 1957 sea-water samples a coccolithophorid was isolated which appeared, under the light microscope, very similar to this newly described coccolithophorid but which possessed, as does the genus Chrysochromulina, a coning haptonema in addition to the two flagella. Electron micrographs, taken for us by Prof. I. Manton, have shown that the holococcoliths from our organism are identical in structure with those from the Crystallolithus hyalinus (cf. PL I, and Gaarder and Markali, 1956, pi. I).