Määritelmä: A cell shape that approximates a cylinder. (Sun, J. and Liu, D. 2003. Geometric models for calculating cell biovolume and surface area for phytoplankton, J. Plankton Res., 25, 1331–1346, doi:10.1093/plankt/fbg096, Table II)
Määritelmä: Colonial organisms are clonal colonies composed of many physically connected, interdependent individuals. The subunits of colonial organisms can be unicellular, as in the alga Volvox (a coenobium), or multicellular, as in the phylum Bryozoa. The former type may have been the first step toward multicellular organisms