Coolia monotis is an armoured, marine, benthic dinoflagellate species. C. monotis cells are lens shaped and anterio-posteriorly compressed. The hypotheca is slightly larger than the epitheca. The thecal surface is smooth and contains numerous randomly spaced pores. Marginal pores are present on both sides of the lipped cingulum. Pores come in two shapes either oblong or spherical. Oblong pores are ~0.5µm in length and spherical ones are ~ 0.3µm across.