Genus: Arrangement of 4 daughter cells flat and rectangular in shape, forming composite coenobium;
without gelatinous sheaths, no hairly projections (Illustrations of the Japanese Freshwater Algae, 1977).
Crucigenia fenestrata Schmidle ? (or Tetrastrum ?),
cell body 4.5 μm long, 3 μm wide,
x 640, Shinobazu-ike (pond), Ueno, Taito-ku, Tokyo, Japan, March 2001 by Y. Tsukii
94 μm; x 640