TJic Diatoms of Nebraska 69 



In rivers, ponds, etc., among filamentous algae : Clear Lake. Dismal River, 

 Grand Island, Hackberry Lake, Halsey, Seneca, Snake River. 

 Fossil : Cherry County, Mullen. 



12. Navicula subcapitata (Greg.) Ralfs in Prifcli. Inf., p. 002. 



1845. 

 Pinnularia subcapitata Greg, in Mic. Jour., pi. 5, fig. 30. 18^6. 

 Navicula hilscana Janisch according to Clcve Syn. Nav. Diat., 



II, p. 175. 

 PI. 8. figs. 254-259. 



Linear, sometimes slightly constricted in the middle, with at- 

 tenuate or capitate apices, 25-50 ju. long, 5-9 /x. wide; costae 9-18 

 in 10 /x, slightly radiate toward the middle, converging at the ends, 

 lacking in the center, forming a pseudostauros. 



In ponds and creeks: Ainsworth, Clear Lake, Hackberry Lake, Lincoln. 

 Long Pine, Tekamah. 

 Fossil : Cherry County. 

 Devils Lake, N. Dak. 



13. Navicula appendiculata (Ag.) Kiitz. Bacill., p. pj, pi. ^, 



fig. 28; pi. 4, fig. 2; pi. 5, fig. 5. 1844. 



Cynibclla appendiculata Ag. Icon. Alg. Eu., pi. i. 1828. 



PI. 8, figs. 260-263. 



Linear or slightly lanceolate, often slightly constricted in the 

 middle. 18-44/i, long, 4-8^0. wide; apices more or less rostrate- 

 capitate ; costae delicate, radiate in the center, converging at the 

 ends, 13-18 in 10 /x, becoming shorter toward the center, where 

 they are entirely lacking, leaving a pseudostauros. The specimen 

 represented in fig. 262 is elliptical and broader than the type. 



In creeks, ponds, tanks, etc.: Brock, Crete, Emerald, Rupert, Stroms- 

 burg. 



Fossil : Loup City. 

 Turtle River, S. Dak. 



14. Navicula braunii Grun. in V. H. Svn., p. yp, pi. 6, fig. 21. 



1885. 



PI. 8, figs. 264-266. 



Lanceolate, slightly swollen in the middle with ends more or less 

 capitate, 35-50 /x long, 8-9 fx wide ; costae radiate in the center, con- 

 verging at the ends, extending nearly to the raphe at the ends, but 



