The Diatoms of Nebraska 8i 



Fossil : Agate, Cherr)^ County, Hay Springs, Loup City, Merriman, 

 Mullen, Thedford, Valentine, Williams's Canyon. 



Little White River,\ Rapid City, Rosebud, Turtle River, S. Dak. ; Chey- 

 enne. Wyo.; Sully's Hill. N. Dak. 



40. Navicula amphibola CI. Diat. of Finl., p. S3, i8pi. 

 Navicula punctata asyniinetrica Lagerst. Diat. of Spots. 18/3. 

 Navicula gastrum styriaca Gnm. Diat. Ocst. und Frans Josef 



Land. 

 PI. 9, figs. 353-355- 



.Valves elliptic-lanceolate, 37-70 ij, long, 23-27 /x wide; apices 

 varying from acuminate to rostrate-capitate; striations radiate, 

 5-10 in 10 /x, coarsely punctate, puncta 12-15 in 10 ju,; striations 

 extending nearly to the raphe, about three of the central ones short- 

 ened opposite the central nodule, leaving a transverse space slightly 

 broader outward. 



Dismal River, Hackberry Lake, Loup River at Thediorcl. 

 Fossil : Agate, Cherry County, Hay Springs, Merriman, Valentine, 

 Williams's Canyon. 



3. Lyratae 



41. Navicula pygmaea Kiitz. Spec. Alg., p. 77. 184^. 

 PI. 9, figs. 356-359. 



Elliptical, sometimes slightly attenuate at the ends, 20-45 I'- ^^ng, 

 8-12 /x wide; striations finely punctate, 18-26 in 10 jx, nearly per- 

 pendicular in the middle and becoming radiate at the ends, inter- 

 rupted on each side of the raphe by a sulcus which nearly touches 

 the raphe in the middle and at the ends and is curved outward 

 between these points. Cells often cohering, forming short fila- 

 ments. 



In stagnant or running water with Oscillatoria, etc. : Culbertson, Dismal, 

 River, Dunning, Grand Island, Humboldt, Lincoln, New Helena, Norfolk, 

 Pleasant Dale, Rupert, St. Paul, Salem, Seward, Stanton, Stromsburg, 

 Talmage, Trenton, Weeping Water, West Point. 



Stockton, Cal.; Devils Lake, N. Dak. 



4. Stauroneideae 



A. Striations more distant in center. 



b. Elliptical. 42. A'', cnicicuta. 



bb. Margins undulate. 43. A'', intcgra. 



A A. Striations lacking in the center. 44. iV. rofacana. 



