The Diatoms of Nebraska 145 



14. NiTZSCHIELLA 



30. Homoeocladia acicularis (Kiitz.) Kuntze. Rev. Gen. Plant., 



Ill,, p. 408. 1898. 

 Nitcschia acicularis (Kiitz.) W. Sm. Brit. Dial., I, p. 4^, pi. 



15, fig. 122. 18^3. 

 Synedra acicularis Kiitz. BacilL, p. (5?, pi. 4, fig. 5. 1844. 

 PI. 20, figs. 772-774- 



Lanceolate, 50-85 fi long, apices attenuated into a long rostrum 

 the length of which is very variable ; keel marginal with small clots, 

 12-18 in 10 fx; striations not easily visible, but according to W. Sm., 

 I.e., there are 40 in 10 /a. 



Common especiall}' with Oscillatoria and other bUie-green algae. In 

 salt marsh at Arbor: Arago, Arbor, Ashland. Auburn, Blue Springs, 

 Brock, Burge, Cherry County, Fairbury, Grand Island, Humboldt, Julian, 

 Lincoln, Rulo, Salem, Seneca, Talmage, Weeping Water. 



Stockton, Cal. ; Emporia, Kansas. 



15. Homoeocladia 



31. Homoeocladia filiformis W. Sm. Brit. Diat., II, p. 80, pi. 5S> 



fig. 348. i8=f6. 



PI. 20, figs. 77S-777- 



Cells in groups of 2-4 enclosed in simple gelatinous filaments. 

 Valves linear or lanceolate with apices more or less acute, 49-100)11 

 long, 4-6 IX wide; keel central with 5-7 dots in lOju; striations fine. 



In creek, Fairbury. 



Family 8. SURIRELLACEAE 



Cells free-swimming, symmetrical to the longitudinal axis, oval, 

 elliptic, or nearly circular, in girdle view straight, spirally twisted, 

 undulate, or saddle-shaped. Rachis a narrow, unmarked strip ; 

 valves with two lateral wing-keels, each enclosing a slit. 



35. Sphinctocystis (Cymatopleura) 



Sphinctocystis Hass. Brit. Freshzv. Alg., p. 436, pi. 102, fig. 5. 

 1845. 

 Cwiatoplcura W. Sm. in Ann. and Mag. N'af. Hist., p. 75J. 

 '185 1. 



