The specific identity of the algal symbiont in <i>Convoluta roscoffensis</i>

Abstract

The algal symbiont of Convoluta roscoffensis (Graff) has been studied with the light and electron microscopes both in situ in worms collected from four localities on the coast of Brittany and in various forms of isolates in culture. The same organism has also been obtained from populations of free-living monads collected from sand and water samples adjacent to the Convoluta colonies. Its structure and behaviour in culture are described and illustrated. Platymonas convolutae sp.nov. is a very distinct species with a rough-surfaced theca and a pyrenoid with some new characters not previously recorded in other members of the group. Some new information on scale and theca production from the Golgi system has also been obtained.