Structure and function of the tentacle and pinnules ofSiboglinum ekmanijägersten (pogonophora) with special reference to the feeding problem

Abstract

The fine structure of the tentacle and pinnules of Siboglinum ekmani is described in detail. It is shown that there are signs of micropinocytosis on the surface of both pinnules and tentacle. Furthermore microvilli are described; in the pinnules they actually form a real brushborder. Blood spaces are found between two lamellae of the tentacular basement membrane. Diverticula from this interlamellar space extend into the unicellular pinnules. A secondary longitudinal subdivision of the intrapinnular space enables the blood to pass from one of the blood spaces in the tentacle through the pinnules into the other tentacular blood space. — It seems very probable that the species in question takes up food through the surface of tentacle and pinnules as was suggested by Ivanov (1955) and Jägersten (1956).