138 Clarence J. Elmore 



Linear, 120-300 /x, long, slightly sigmoid, obtusely rounded at 

 both ends; keel more or less excentric with 5-6 dots in 10 ft; stri- 

 ations 26-27 in 10 jx. No specimen yet found in Nebraska attams 

 this size. Represented here by var. brei'issima, which is short- 

 linear, slightly curved and constricted in the middle, 27-28 /x long, 

 5-6 /A wide, with 8-10 dots and about 30 striations in 10 /a; apices 

 apiculate. 



Damp ground, tanks, creeks, etc. : Ainsworth, Anselmo, Dunning, Ewing, 

 Grand Island, Lakeside, Long Pine, Louisville, Stromsburg, Valentine, 

 West Point. 



7. Spectabiles 



14. Homoeocladia spectabilis (Ehr.) Kuntze. Rev. Gen. Plant., 



Ill, p. 40p. iSp8. 



Nitsschia spectabilis (Ehr.) Ralfs in Pritch. Inf., p. 782. 1843. 



Syncdra spectabilis Ehv. Verb, (figures only). 1843. 



PL 19, figs. 711-712. 



Linear, slightly curved, 160-306 /a long, ii-i5/tt wide, apices 

 cuneate, attenuate, often rostrate ; keel marginal with large dots 

 sometimes slightly prolonged, 3-7 in 10 /a; striations 11-15 in 10 /x. 



In lakes, creeks, rivers, also fossil : Ainsworth, Anselmo, Clear Lake, 

 Dunning, Emmett, Hackberry Lake, Halsey, Long Pine, Newport, O'Neil', 

 St. Michael, St. Paul, Thedford, Whitman. 



Fossil : Agate, Cherry County, Hay Springs, Merriman, Mullen, Spald- 

 ing. 



Little White River, S. Dak. ; fresh water near Devils Lake, X. Dak. ; 

 Stockton, Cal. 



8. DUBIAE 



A. Carinal dots elongated; valves broad. 15. H. dubia. 

 A A. Carinal dots round; valves elongated. 



b. Small, striations fine, distinctly rostrate. 16. H. conimutata. 



bb. Medium size, sub-rostrate. 17. H. iimbonata. 



15. Homoeocladia dubia (W. Sm.) Elmore. 



Nitcschia dubia W. Sm. Brit. Diat., I, p. 41, pi. 13, fig. 112. 

 PI. 19, fig. 725. 



Linear, ventral side nearly straight, dorsal side slightly convex, 

 slightly constricted in the middle, 90-160 /x long, about 15/x wide, 



