Genus: 
Variable in shape; strong constriction at center; semicell ellipsoidal, polygonal, etc.; 
cell wall with simple or branching spines, most of them laterally aligned; 
4 plate-like chloroplasts in each semicell; one or more pyrenoids in each chloroplast 
(Illustrations of The Japanese Fresh-water Algae, 1977). 
Species (var. antilopauem) : 
Cell body 45-72 μm long, 43-71 μm wide, L/W = 1, 
constriction 13-25 μm wide, spines 19-22 μm long, 
semicells with 4 spines (2 anterior, 2 basal), 
cell wall at the center of semicells thickened and punctated 
(Illustrations of The Japanese Fresh-water Algae, 1977). 
 
	