Flimmer-flagellum of the Sponge

Abstract

THERE is a considerable variation in the morphology of the flagella in the lower plant groups and in the flagellates. The flagellar structures have been used as systematic characters since the pioneering work of Petersen¹ and Vlk². The following five types of flagella are recognized: (1) One-sided flimmer flagella which have one row of hair-like appendages (called flimmer hairs or mastigonemata or, somewhat misleadingly, cilia). The flimmer hairs are about 3µ long, and the row extends along the entire length of the flagellum on its one side. (2) Two-sided flimmer flagella which have two rows of flimmer hairs along the entire length of the flagellum. (3) Whip flimmer flagella which have a demarcated thin end region devoid of flimmer hairs and a main region which possesses two rows of flimmer hairs. The flimmer hairs stand perpendicular to the flagellar axis. (4) Whip flagella which are devoid of flimmer hairs but have a demarcated thin end region. These flagella are also called lash flagella. (5) Flagella which lack flimmer hairs and also lack a demarcated end region visible in the light microscope.