92 



Clarence J. Elmore 



don Creek, Grand Island, Hackberry Lake, Halsey, Hemingford, Long 

 Pine, Oakdale, Pelican Lake, Red Cloud, St. Paul, Seneca, Snake River, 

 Thedford, Valentine, Wann, Whitman. 



Fossil : Agate, Greeley County, Hay Springs, Loup City. 



Belvidere, Little White River, Scenic, S. Dak. ; Court Lake, N. Dak. ; 

 Stockton, Cal. 



64. Navicula dubia Ehr. Amcr., p. 130, pi. II, 2, fig. 8. 1843. 

 PI. 12, fig. 440. 



Elliptical, sometimes slightly biconstricted, 27-37111 long, 10-12 fx. 

 wide ; raphe straight, the central ends bent in opposite directions ; 

 striations punctate, oblique, 16-24 in 10 fx, interrupted near the 

 margin of the valve by a deep sulcus, scarcely shortened opposite 

 the central nodule. Dried valves tisually brown. 



Pool, Crete. 



13. Bacilleae 



A. Linear, terminal nodules not expanded laterally. 65. A^. bacilliformis. 

 AA. Swollen in the middle ; terminal nodules expanded laterally. 



66. A'', pupula. 



65. Navicula bacilliformis Grun. in CI. & Grim. Arct. Diat., p. 44, 



pi. 2, fig. 51. 1880. 



PI. 12, figs. 441-442; pi. 22, fig. 836. 



Linear with broad rounded ends, sometimes slightly gibbous at 

 the ends and in the middle, 30-45 /x long, 7-10 /a wide; striations 

 slightly radiate, usually slightly converging at the ends. 12-16 in 

 10 II. shortened opposite the central nodule, leaving a rectangular 

 hyaline space' about one-half the width of the valve. 



In lakes, creeks, rivers, etc., also fossil : Ashland, Central Cit}', Clear 

 Lake, Columbus, Crete, Dunning, Fremont, Grand Island, Hackberry Lake, 

 Hemingford, Long Pine, Louisville, O'Neill, Oakdale, St. Paul, Sheridan 

 County, Stanton. Talmage, Thedford, Whitman. 



Fossil : Loup City, Greeley County, Hay Springs, Merriman, Mullen. 



Belvidere, Rosebud, S. Dak. ; fresh water near Devils Lake, N. Dak. 



66. Navicula pupula Kiitz. BacilL, p. pj, pi. 50, fig. 40. 1844. 

 PI. 12, figs. 443-447- 



Linear, usually swollen in the middle and at the ends, 19-37 /"- 

 long, 7-9 ju, wide, apices broadly rounded or nearly truncate; stri- 

 ations radiate, 18-23 in lO/x, shortened opposite the central nodule, 



