POLYMORPHISM IN MASTOGLOIA(1)

Cells in a -wild population of a species belonging to the diatom germs Mastogloia may form frustules of 2 strikingly different morphologic types during their vegetative life cycle. Total conversion from coarsely structured morphologic form to a more finely structured form takes place during a single division; hence no inter gradations between the 2 forms are evident. Intact frustules with 1 valve of each type leave no reasonable doubt of the ability to make the change.