Observations with the Electron Microscope on a Species ofSaprolegnia

Abstract

Electron micrographs are presented to show the morphology of the flagella in each of the two motile phases of Saprolegnia ferax , and one visual light photograph of a stained cell of the second stage is added. The front flagellum of both phases is a Flimmergeissel with hairs between 2μ and 3μ long arranged in two rows and each ending in a thin hair-point. The axis is covered by a wide transparent sheath made of some material which appears to liquefy after death. The hind flagellum, which is devoid of Flimmer , is covered by a similar sheath, though there are signs that this is flattened into a fin in the hind flagellum of the second stage. Some very fine short hairs 0·5μ long are interpreted as a possible internal framework to this fin. The axis of both flagella is fibrillar, but accurate numerical details have not yet been obtained. The skins discarded from cysts have also been examined and shown to be covered with characteristic double-headed hooks, which are strong enough to attach a cyst to passing objects.