{88}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. STAURONEIS PHOENICENTERON EHR. Valve lanceolate, obtuse; striæ radiate, 18 in 10 µ, distinctly punctate. L. usually 125 µ but sometimes 200 µ. Common in fresh water. Pl. 27, Fig. 1. STAURONEIS ANCEPS EHR. Valve lanceolate, with rostrate or capitate ends; stauros in some cases does not reach the margin. The varieties are very numerous. _Var. gracilis (Ehr.) Cl._--Valve lanceolate, striæ very fine; margin of stauros striated. L. 100 µ. Cape May, N. J. Pl. 27, Fig. 5. _Var. amphicephala (Kuetz.) Cl._--Valve capitate at the ends; striæ, 24 in 10 µ. L. 47 µ. Fresh water. Pl. 27, Fig. 7. _Var. ?_--Valve with produced ends; striæ, 30 or more in 10 µ. L. 104 µ. Willistown, Pa. Pl. 27, Fig. 4. _Var. ?_--Valve with produced ends; striæ, about 28 in 10 µ, punctate. L. 47 µ. Newtown Square. Pl. 27, Fig. 8. _Var. ?_--Valve with produced ends; striæ, 22 in 10 µ, showing a tendency to form longitudinal rows of puncta as in Stauroneis stodderi Greenleaf, but the rows are not so evident. L. 60 µ. Pavonia, N. J., artesian well. Pl. 27, Fig. 9. STAURONEIS FRICKEI VAR. ANGUSTA N. VAR. Valve lanceolate, gradually tapering to the obtuse ends; terminal fissures prominent, forking at a distance of 7 µ from the ends. Frustules frequently geminate. L. 173 µ. Newtown Square. Rare. Pl. 26, Fig. 18. Near Stauroneis frickei A. S. (Atlas, Pl. 242, Fig. 16), except that the stauros is narrow at the margin. {89}STAURONEIS SALINA WM. SM. Valve lanceolate, obtuse; stauros narrow, with short, scattered striæ at the margin, 18 in 10 µ, punctate. L. 65 µ. Along the coast. Common. Pl. 27, Fig. 6. STAURONEIS LEGUMEN EHR.