114 r. T. Cl. EVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



^j. i Size small (L. 0,0 G to 0,2 mm.) lö. 



''• \ — large (L. 0,3 to 0,5 mm.) 18. 



.. , J Valve witb gradually iiarrowed emls G. Spencerii W. Sm. 



■ \ — — obliquely rouniled — 17. 



J Lengtli 0,00 mm G. scalijroides Rabh. 



\ — 0,14 — G. Temperei CJl. 



..„ I Traiisversft striiE about i) in 0,01 mm 'G. Grovei Cl. 



' \ — — — 18 — G. spectabile Grux. 



J Median liiie sinuose G. dimimttnm Geun. 



"■ 1 - - not - 20. 



^ \ Valve verv narrow, 17 or more times longer tlian broad G. lineare Grun.. 



~ ■ I — less narrow 21. 



jj. J Median line sligbtly exeentric 22. 



" '\ — — coineident witli tlie margin 24. 



j, I StriiB equidistant 23. 



\ Transverse stria; wider tlian tlie longitudiual G. arcticmn Cl. 



4,., j Stris about 12 in 0,oi mm G. robiistum Grun. 



•"I — — 20 — G. WansbecJcii Donk. 



, J Frnstule arcuate 25. 



^^- 1 - not 2G. 



f Valve broad, unilaterally rounded G. compactum Grev. 



\ — narrow, lanceolate G. meäiferrnncvm Cl. 



J Transverse and longitndinal stri» equidistant G. rectum DoxK. 



\ — striiB narrower tlian tlie longitndinal G. angustuiii DoxK. 



1. G. aciiiiiiiiatiim Kutz. (1.S33). — V. sigmoid, laneenlate, gradually tapering to tlie ohtuse 

 ends. L. O, i to O, it^; B. (),oi.-) to 0,02 mm. Median line central, sigmoid, Transverse and longi- 

 tndinal strife equidistant, about 18 in 0,oi mm. — Frushdia acuminata KiJTZ. Linnfea VIII p. Söii 

 Dec. N:o 84 (accord. to Lägst.). Pleuros. acuminainm Grun. A. D. p. 56. V. H. Syn, 117 Pl, 

 XXI f, 12. Per. VII f. 36, 37. Flenr. Jacrustre W, Sm, B. D, I Pl, XXI f, 217, Fleitr. frans- 

 sylvanicum Pant, III Pl. VI f. 94? 



Fresli water: Sweden! England! Saxony! 



Var. curta Grun, (1880). — L. 0,og3 to O.osg; B, 0,0145 mm. Ends sttbrostrate, obtuse. 

 Striie 18 in 0, 01 mm, 



Fresh water: Holstein (Grun.). 



Var. gallica Grun. — V. sigmoid, lanceolate, with attenuate, subacute ends. L. O.on to 

 0,ir, .=>; B. 0,011 to 0,oi8 mm. Median line sigmoid, central. Longitudiual and transv, strise equi- 

 distant 20 to 21 in 0,01 mm. — P. scal^yrum var. gallica Grun. V. H, T. X:o 172. P. gallie. 

 Per. VII f. 2. 



Fresh and brackish water: Sweden (Hernösand, fossil, Rimforsa i Vestergötland, Ringsjön)! 

 France (V. H. T,), Argentina! 



Var, Brehissonii Grun, (1880). — V, sigmoid, linear-lanceolate, witli subacute ends. L. 0,086 

 to 0,104; B, 0,011 to 0,013 mm. Median line central, sigmoid. Transverse and longit. stritB equi- 

 di,sstant, 22 to 23 in 0,o 1 mm. — Flcuros. halHcum y W. Sm, B, D. XXII f, 207 y, P, Brch. Grun. 

 A, D, p. 56. Per. VII f, 29, 30? P. halt. var. Bréh. V, H. Syn. p. 117 Pl. XXI f. 6. P. ftralp- 

 rmn Rabii. A, Eur. N:o 2013 (accord. to Grun.). 



Fresh or slightly brackish water: Spitzbergen! Sweden! Paris! Saxony! Argentina! 



2. G. Terryaimm Per. (1891). — V, slightly sigmoid, tapering from the middle to the 



obtuse ends. L. 0,4 to 0,45; B. O, o as to 0, 041 mm. Median line central, fiexuose near the central 

 nodule, which is obliquely elongated. Ti^ansvei^se and longit, .stritv equidistant, 14 in 0,oi mm, — 

 Fhnros. Tvrr. Per. p. 18 Pl, VII f, 21. 

 Marine: Connecticut! 



3. G. Baileyi Grxtn. (1880). — V, broadly lanceolate, strongly sigmoid, with subacute ends, 

 L. 0,08 to 0,13; B. 0,0 18 to 0,021 mm. Median liue central, sigmoid. Central nodule large. 



