Tiic Diatoms of Nebraska 133 



Belvidere, Blackpipe, Imlay, Interior, Little White River, Norris, Red- 

 leaf, Rosebud, Scenic, Turtle River, Weta, S. Dak. ; Devils Lake, fresh 

 water near Devils Lake, N. Dak. ; Cheyenne, Wyo. ; Stockton, Cal. ; New 

 Concord, Rio Grande, Ohio. 



2. Homoeocladia virgata (Roper) Kuntze. Rev. Gen. Plant., 



Ill, p. 4op. i8p8. 

 Hantsschia virgata (Roper) Grun. in CI. & Griin. Arct. Diat., 



p. 104. 1880. 

 Nitsschia virgata Roper in Mic. Jour., VI, p. 2^. 18^8. 

 PI. 18, fig. 681. 



Robust, arcuate, 66-130 |U, long, 13-20 /a wide, apices strongly 

 rostrate, obtuse, keels of the tw^o valves on the same side of the 

 cell, with elongated dots, 4-5 in 10 /m, the two central dots slightly 

 more separated; striations 9-1 1 in 10 /x,. 



In pond, Orella. 



2. Tryblionella 



A. Striations composed of coarse puncta. 3. H. punctata. 

 AA. Striations not of coarse puncta. 



b. Striations extending across the entire valve. 4. H. angustata. 



bb. Striations interrupted by a sulcus. 5. H. tryblionella. 



3. Homoeocladia punctata (W. Sm.) Kuntze. Rev. Gen. Plant., 



Ill, p. 409. 1898. 

 Nitcschia punctata (W. Sm.) Grun. in CI. & Grun. Arct. Diat., 



p. 68. 1880. 

 Tryblionella punctata W. Sm. Brit. Diat., I, p. ^6, pi. ^o, fig. 



261. 18^^. 

 PI. 18, figs. 682-686. 



Elliptical to elliptical-lanceolate, 25-40 /a long, 7-30 /a wide, 

 apices acute or acuminate ; keel marginal with the dots corre- 

 sponding with the striations, which are formed of coarse dots, 

 7—10 in 10 |U,. 



Ponds : Pleasant Dale, Grand Island. 

 Fossil : Thedford. 



4. Homoeocladia angustata (W. Sm.) Kuntze. Rev. Gen. Plant., 



Ill, p. 408. 1898. 

 Nitcschia angustata (W. Sm.) Grun. in CI. & Grun. Arct. Diat., 

 p. 70. li 



