Originally described by Lemmermann in 1910, Schiller in 1937, Whitford and Schumacher, 1969 and Campbell in 1974. The cells are large, 30µ wide, 38µ long. They are considered a winter form because they were frequently found in cold waters. However, Whitford and Schumacher found them in water temperatures above
20°C in summer. This species is distinctive because of their small posterior spines. This sample was collected in Muddy Creek off Rhode River.