TJic Diatoms of Nebraska 129 



Little White River, Rosebud, S. Dak. ; Cheyenne, Wyo. ; fresh water 

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



6. Cystopleura argus (Kiitz.) Kuntze. Rev. Gen. Plant., II, p. 



8pi. i8pi. 



Epithemia argus Kiitz. BacilL, pi. 2g, fig. ^^. 1844. 



PI. 17, fig. 661 ; pi. 23, figs. 850-855. 



Dorsal margin slightly arcuate, ventral margin nearly straight, 

 40-70 fjL long, apices obtuse ; costae slightly radiate with capitate 

 apices, 1-2 in 10 /a; striations granular, 10-14 in 10 ju,. 



Lakeside, Woodlake. 



Fossil : Hay Springs, Merriman. 



Fresh water near Devils Lake, N. Dak. 



7. Cystopleura zebra (Ehr.) Kuntze. Rev. Gen. Plant., II, p. 



8pi. i8pi. 

 Navicula zebra Ehr. Abh., p. 262. 18 j^. 

 Epithemia zebra (Ehr.) Kiitz. BacilL, p. ^4, pi. 5, fig. 12; pi. 



30, fig- 5- 1^44- 



PI. 17, figs. 662-667. 



Curved, 35-70 ju, long, 8-12 jx wide ; dorsal margin strongly con- 

 vex, ventral more or less concave; apices somewhat capitate; 

 pseudoraphe distinct, incurved, forming an angle at the center ; 

 costae heavy, 3-4 in 10 /a; striations coarsely granular, 12-14 in 

 10 /A. Var. proboscidea is a more curved form. 



Li creeks, rivers, ponds, etc., also fossil : Benkleman, Burge, Clear Lake, 

 Crawford, Dismal River, Dunning, Gibbon, Grand Island, Halsey, Holt 

 County, Hyannis, Lakeside, St. Paul, Seneca, Snake River, South Bend, 

 Talmage, Thedford, Trenton, Valentine, Wann. 



Fossil : Agate, Cherry County, Hay Springs, Loup City, Merriman, 

 Mullen, Thedford. 



Blackpipe, Cutmeat, Norris, S. Dak. ; Court Lake, Devils Lake, N. Dak. ; 

 Ft. Collins, Colo. ; Stockton, Cal. 



8. Cystopleura gibberula (Kiitz.) Kuntze. Rev. Gen. Plant., II, 



p. 8pi. i8pi. 

 Epithemia gibberula Kiitz. BacilL, p. 55, pL 2p, fig. ^4; pi. jo, 



fig. 3. 1844. 

 PI. 17, figs. 668-669. 



Valves strongly lunate. 20-70 /a long ; dorsal margin very 

 strongly curved, ventral margin nearly straight, gradually tapering 



