TJic Diatoms of Nebraska 55 



been found (figs. 110-114) in tanks at Central City and Stroms- 

 biirg, Nebraska, and in Put-in Bay, Ohio. 



In tanks, ditches, ponds, creeks, and rivers : Cairo, Central City, Craw- 

 ford, Halsey, Meadow, North Platte, Red Cloud, Scottsbhiflf, Seneca, 

 Talmage, Tekamah, Thedford. 



Fossil : Mullen. 



Cheyenne, Wyo. ; Chippewa Falls, Wis. ; Weta, S. Dak. ; Sully's Hill, 

 N. Dak. ; Fresno, Stockton, Cal. ; Put-in Bay, Ohio. 



4. Synedra familiaris Kiitz. Bacill., '*p. 68, pi. ij, fig. 12. 1844. 

 PI. 3, fig. 115. 



Linear-oblong or lanceolate, 37-80 /t long, apices attenuate-ros- 

 trate or capitate; striations 13-17 in 10 ju,, lacking in the middle, 

 leaving a clear space ; center contracted or sometimes swollen ; 

 pseudoraphe narrow ; cells sometimes cohering in short bands. 



Ill tanks, rivers, etc.: Clear Lake, Dewey Lake, Dismal River, Halsey, 

 Long Pine, Melia, O'Neill, Talmage, Tekamah, Thedford. 

 Fossil : Greeley County. 



5. Synedra ulna (Nitz.) Ehr. Inf., p. 211. 18^8. 

 Bacillaria ulna Nitz. Bcitr., p. pp. i8iy. 



PI. 3, figs. 11^130; pi. 4, figs. 131-139- 



Narrowly linear or somewhat lanceolate with ends more or less 

 elongated-rostrate, sometimes capitate, 50-350 jx long ; striations 

 distinct, 9-10 in 10 /x, leaving a narrow pseudoraphe. usually lack- 

 ing in the middle, leaving a rectangular clear space. Very variable 

 and presenting many forms that have been described as species or 

 varieties; among these are danica, figs. 118, 123, 132, 133. and 

 splcndcns, figs. 116, 117, 131. It is impossible to separate these 

 forms from one another. Some of them can be distinguished 

 from vS'. tcmussima only by their coarser striations. 



Common in tanks, creeks, ponds, etc.. with various algae : Andrews, 

 Anselmo, Arago, Ashland, Battle Creek, Bellevue, Benkleman, Brock, Broken 

 Bow, Burge, Cedar Creek, Central City, Clear Lake, Cody Lake, Columbus. 

 Crawford, Crete, Dewey Lake, Dismal River, Dunning, Emerald, Emmett, 

 Ewing, Fairbury, Fremont, Gordon Creek, Grand Island, Hackberry Lake. 

 Haigler, Halsey, Holt County, Hyannis, Lakeside, Lincoln, Lodi, Long 

 Pine, Meadow, Melia, Milford, New Helena, Newport, Norfolk. North 

 Platte, Northport, Oakdale, O'Neill, Orleans, Pelican Lake, Phalaris Lake, 

 Pleasant Dale, Red Cloud, Ruby, Rupert, St. Michael, St. Paul, Scottsbluff, 



