Raphe-like vestiges have been found regularly in two new taxa which presumably belong to Fragilaria, one of them living in several lakes of the Kerguelen Islands, the other in the Yellowstone National Park, Wyoming, U.S.A. The latter one possesses septa-like elements as integrated parts of a girdle band. Other septa-like elements can occur in different species of Fragilaria. They represent appendices of the valvocopula, located beneath the transapical costae. Structures like linking spines on marginal parts of the valve face occur in an Achnanthes species. Most of these characters seem to have been unknown in these taxa until recently.