"alexandrium monilatum" are armored or thecate dinoflagellates with an outer cell wall covered with cellulose plates. "a. monilatum" is wider at the cingulum or equatorial girdle than it is tall, and it commonly joins into chains of from two to sixteen individuals, with chains as long as 32 cells in calm seas. the cingulum or groove halfway between the top and bottom of the organism's single cell is where the pair of flagella are situated. to form chains, "a. monilatum" cells exude a glue from the apical or top attachment pore of one individual to make it adhere to the antapical or bottom attachment pore of the next individual in the chain. organisms produced in laboratory cultures do not usually form chains. the nucleus is located in the center of the cell, and "a. minilatum"'s many chloroplasts radiate outward from the nucleus. a bioluminescent strain of "a. monilatum" has been identified from mississippi sound in the gulf of mexico.