Family: Colonial, usually with a gelatinous coat; 4 daughter cells are connected with filaments derived from their maternal cell wall; cell body spherical, elliptical or heart-shaped; a single chloroplast plate-like or cup-shaped containing a pyrenoid; asexual reproduction by autospore, sexual reproduction by fertilization of egg and sperm.
Genus: Planktonic; colony of 16, 32 or 64 cells, irregular in shape, without gelatinous sheath; colony consists of subsets of 4 cells connected by gelatinous filaments extending from the center; each subset consists of cells of two types, 2 cells located outward, kidney- or heart-shaped, other 2 cells located inward, cylidrical, both ends rounded; a single chloroplast plate-like in shape, slightly curved, with a pyrenoid (Guide book to the "Photomicrographs of the Freshwater Algae", 1998).

D. lunatus 1 clip 20 x 6 μm Higashi-hiroshima Hiroshima, 1998