Give a brief account of dinoflagellates.

* These are mostly marine and photosynthetic.

* They appear yellow, green, blue or red depending on the main pigments present in their cells.
* Cell wall has stiff cellulosic plates on the outer surface. They have two flagella, one lies longitudinally and the other transversely in a furrow between the wall plates.
* These are called as whirling whips due to spinning movements of flagella.
* Nucleus also called as mesokaryon.
* Noctiluca show bioluminescence.
* Red tides of Mediterranean sea is due to inhabitation of Gonyaulax. Toxins released from them may kill other marine animals such as fishes.