The Diatoms of Nebraska 147 



■ -> ■> 



Fnistulia qiiinquc punctata Kiitz. in Linnaca, p. f^^^. 18^^ 



PI. 20, figs. 779-784. 



Oblong, more or less constricted in the middle, 39-169 /u, long 

 (according to De Toni, Syll. Alg., II, p. ^pQ, 300 /a long), 14-31 /x 

 wide, apices rounded or slightly apiculate ; marginal beads about 

 8 in 10 /x; striations perpendicular to the margins, 8-9 in 10 /x, 

 indistinct or lacking in from 2 to 4 spots in the middle of the 

 valve ; valves undulate, as is clearly seen in girdle view. Very 

 variable, showing all gradations from the short form in fig. 780 to 

 the long one in fig. 779. 



In creeks, rivers, ponds, pools, etc., also fossil : Andrews, Anselmo, Ash- 

 land, Blue Springs, Brock, Cairo, Callaway, Crawford, Crete, Culbertson, 

 Dismal River, Dunning. Emerald, Fairbury, Fremont, Gordon Creek, Grand 

 Island, Johnson, Lincoln, Long Pine, Nemaha City, New Helena, Norfolk, 

 North Platte, Oakdale, Orleans, Plattsmouth, Rulo, St. Paul, Seneca, Snake 

 River, South Bend, Stanton, Stromsburg, Talmage, Thedford, Valentine, 

 Wahoo, Wann, Weeping Water. 



Fossil: Greeley County, Hay Springs, Loup City, Mullen, Spalding, 

 Valentine. 



Blackpipe, Little White River, Rapid City, Rosebud, S. Dak. ; Devils 

 Lake, N. Dak. ; Cheyenne. Wyo. ; Stockton, Cal. ; Ft. Collins, Colo. ; Black- 

 hand, Muskingum River, New Concord, Ohio ; Emporia, Kansas. 



36. Surirella 



Surirella Turpin. Mem. Mus., p. ^62, tab. 16. 1828. 



Novilla Heib. Consp. Diat. Dan., p. 100. 186^. Stcnoptcrobia 

 Breb. ; Suriraya Pfitzer in De Toni Syll. Alg., II, p. 567. 

 1891. 



Etym., named for Doctor Suriray of Havre, France. 



Cells free or stalked, straight or twisted, in valve view cuneate, 

 renif orm, ovate, elliptical, or linear ; girdle view cuneate, elliptical, 

 oblong, or sigmoid ; valves with beaded or ribbed keel on each 

 margin containing the raphe ; surface with the ribs extending from 

 the margin toward or to the median linear or lanceolate pseudo- 

 raphe. Chromatophores and auxospores as in SpJiinctocystis. 



A. Valves usually plane. 



h. Costae extending to or nearly to the median line. 

 c. The two apices alike. 



d. Small, linear-elliptic. i. S. linearis, 



dd. Large, lanceolate. 2. S. biseriafa. 



