Observations on the Structure of the Zoospores ofVaucheria

Abstract

The motile zoospore of Vaucheria has been studied by means of ultraviolet and electron microscopy. The cilia are shown to be definitely heterokont with an average length difference of 1.3 μ between the two members of a pair; they are arranged in parallel over the spore surface with the shorter cilium of each pair orientated towards the front end of the spore. The internal structure of the ciliary bases is described from serial sections. The arrangement of the other cell organs throughout the spore is discussed in a preliminary way and sufficient structural details are given for identification of mitochondria, fat bodies, nuclei, and plastids. A thin membrane on the spore surface is demonstrated and a somewhat thicker membrane lining the main vacuoles is described and its thickness measured. The structure of the cytoplasm is discussed in a preliminary way.