Considered by Cleve as synonymous with M. apiculata Grun., not Wm. Smith, and by De Toni as synonymous with M. apiculata Wm. Sm. In any case, M. angulata Lewis is not the same as M. apiculata Wm. Sm., the loculi of which are equal.
Atlantic City. H. L. Smith T. S. No. 211.
Pl. [17], Fig. 17.
Stauroneis EHR. (1843)
(stauros, a cross, and neis (naus), a boat)
Frustules free, sometimes geminate; valve as in Navicula but with a stauros. Cell contents as in Navicula. Mereschkowsky, however, says that the chromatophores always contain more pyrenoids than are found in Navicula. Heinzerling gives the number as two to four in each chromatophore.
Cleve includes under Naviculæ Microstigmaticæ all species of Stauroneis, Pleurostauron, Schizostauron, certain Schizonemæ and Naviculæ. As a matter of convenience, and because I have already included certain Schizonemæ and Scoliopleura under Navicula, and because of the small number of species in our locality, I have arranged them under the three divisions of Cleve as follows:
Stauroneis.—Forms having a true stauros, without diaphragms.
Pleurostauron.—Forms like Stauroneis but with diaphragms at the ends.
Schizostauron.—Forms having a bifid stauros.