TJic Diatoms of Nebraska 125 



ScottsblufiF, Seneca, Sheridan County, Snake River, South Bend, Stanton, 

 Stromsburg, Talmage, Tekamah, Tioga, Thedford, Trenton, Valentine, 

 Wann, Watts Lake, Weeping Water, West Point, Whitman, Woodlake. 



Fossil : Agate, Cherry County, Greeley County, Hay Springs, ILoup City, 

 Merriman, Mullen, Spalding, Thedford, Valentine, Williams's Canyon. 



Belvidere, Blackpipe, Cutmeat, Little Wliite River, Norris, Rapid City, 

 Rosebud, Weta, S. Dak. ; Devils Lake and fresh v\rater near Devils Lake, 

 N. Dak. ; Cheyenne, Wyo. ; Fresno, Stockton, Cal. ; Ft. Collins, Colo. ; 

 Blackhand, Granville, Put-in Bay, Rio Grande, Ohio ; Emporia, Kansas. 



2. Amphora salina W. Sm. Brit. Diat., I, p. ip, pi. 30, fig. 251. 



1853- 



PI. 17, fig. 644. 



Cells elliptic-oblong with ends slightly attenuate, 21-50 /x long, 

 3-5 IX Wide ; valves lunate with rostrate, slightly capitate ends ; 

 ventral margin often nearly straight; striations fine, granular, 

 18-21 in 10 II. 



In basin of salt well and in jar in laboratory, Lincoln. 



3. Amphora proteus Greg. Diat. of Clyde, p. ^18, pi. 13, fig. 81. 



1857- 

 PI. 17, fig. 645. 



Cells elliptic with truncate ends, 70-1 50 /a long, 40-60 ^u- wide; 

 valves lunate, ends obtuse; raphe bent, central nodule large, often 

 surrounded by a stauroneiform space ; striations very distinct, 

 granular, 8-10 in 10 /a. 



In Devils Lake, N. Dak. 



33. Cystopleura 



Cystopleura Breb. in Kiitz. Spec. Alg., p. 5. 1849. 



Epithemia Breb. ; Amphicampa Ehr. ; Clhnacidium Ehr. ; Des- 

 mogonium Ehr. 



Etym., from Gr. /cT^Wts, vesicle, and 7r\evpd, rib, a name probably 

 suggested by the clear vesicle-like appearance of the cell with the 

 very prominent ribs. 



Cells single, rarely in short chains, attached ventrally to other 

 plants, girdle view oblong to barrel-shaped. Interzones present or 

 absent; valves lunate, internally transversely ribbed, transversely 

 beaded externally ; raphe excentric, near the concave margin. 



