The Diatoms of Nebraska 113 



11. Gomphonema gracile Ehr. Inf., p. 21"/, pi. 18, fig. j. 1838. 

 PI. IS, figs. 563-566. 



Lanceolate or rhomboidal, 25-92 /x long, 7-13 f- wide, apices 

 nearly alike; striations 7-15 in 10 /a, nearly transverse, those in 

 the middle shortened or slightly more distant, leaving a transverse 

 space in which is an isolated dot, often indistinct. 



In creeks, rivers, tanks, ponds, lakes, etc., also fossil: Broken Bow, 

 Clear Lake, Cody Lake, Dewey Lake, Dismal River, Dunning, Emerald, 

 Emmett, Fremont, Gordon Creek, Grand Island, Hackberry Lake, Hyannis, 

 Lakeside, Lodi, Mason City, New Helena, ' Newport, Orella, Orleans, 

 Pleasant Dale, Rupert, Scottsbluflf, Seneca, Stromsburg, Thedford, Val- 

 entine, Watts Lake, Willow Lake, Woodlake. 



Fossil : Agate, Cherry County, Greeley County, Loup City, ^Mullen. 



Little White River, Norris. Turtle River, S. Dak.; Stockton, Cal. 



12. Gomphonema intricatum Kiitz. BacilL, p. 87, pi. p, fig. 4. 



1844. 



PI. 15, figs. 567-570; pl- 23, fig- 846. 



Slender, linear-lanceolate, 21-87 ^u, long, 4-11 ;u. wide, more or 

 less swollen in the middle, apices rounded; striations 9-12 in to /a, 

 nearly transverse, shortened opposite the central nodule, leaving a 

 rounded space in which is an isolated dot. Very variable in form 

 and size, central area sometimes almost lacking as in fig. 568. 



In creeks, ponds, etc., also fossil : Brock, Crawford, Emerald, Grand 

 Island, Red Cloud, Stromsburg, Talmage, Wann, Woodlake. 

 Fossil : Greeley County. 



13. Gomphonema olivaceum (Lyngb.) Kiitz. Bacill., p. 8=>, pl. 7, 



figs. 13, 15. 1844. 

 Echinella olivacea Lyngb. Tent. Hydr. Dan., p. 2op, pl. jo, 



fig. c, 1-3. i8ip. 

 Pl. 15, figs. 571-574- 



Clavate, rarely sublanceolate, 15-34/x long, 5-8 ju. wide, apex 

 broad and rounded, base narrower; striations 10—14 in' to /a, usually 

 shortened or lacking in the center, forming a pseudostauros, curved 

 or radiate in the middle, the rest nearly transverse. 



Very abundant in creeks, especially in the spring forming brown, gelati- 

 nous masses coating stones, sticks, and the bottom of the stream : Antioch, 

 Ashland, Blue Springs, Cairo, Grand Island, Haigler, Lincoln, O'Neill, 

 Seneca, Valentine, Wahoo, Woodlawn. 



