114 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



„ I Size small (L. 0,06 to 0,2 mm.) .16. 



\ — large (L. 0,3 to 0,5 mm.) 18. 



^^ J Valve with gradually narrowed ends ... . . . G. Spencerii W. Sm. 



\ — — obliquely rounded — ■ 17. 



^„ J Length 0,06 mm . . . . G. scalproides Rabh. 



'■ \ — 0,14 — . G. Temperei Ol. 



.jQ J Transverse stris about 9 in 0,oi mm . . G. Grovei Cl. 



' \ — — — 18 — . . . G. spectabile Gbuk. 



I Median line sinuose G. dimirmUim Gkun. 



19- \ _ _ not - .20. 



f Valve very narrow, 17 or more times longer than broad .... . G. lineare Ghun.. 



) — less narrow 21. 



Median line slightly exeentric 22. 



coincident with the margin . . . , , . 24. 



„.. j Median lin( 



„ J Striae equidistant "3. 



\ Transverse strise wider than the longitudinal ... .... . G. arcticum Cl. 



„„ (Striae about 12 in 0,oi mm. ... ... . . G. rohustum Gbun. 



' \ — — 20 — G. Wansheckii Donk. 



. ( Frustule arcuate . . . . 25. 



"^^^ \ - not 26. 



_. f Valve broad, unilaterally rounded . . . . G. compaetum Grev. 



" \ — narrow, lanceolate . ... G. mediterrnneum Cl. 



I Transverse and longitudinal striae equidistant G. rectum Donk. 



\ — striae narrower than the longitudinal . G. angustum Donk. 



1. G. acuminatum Kutz. (1833). — V. sigmoid, lanceolate, gradually tapering to the obtuse 

 ends. L. 0,i to 0,i8; B. 0,oi5 to 0,o2 mm. Median line central, sigmoid. Transverse and longi- 

 tudinal striee equidistant, about 18 in 0,oi mm. — Frustulia acuminata Kutz. Linnsea VIII p. 555 

 Dec. N:o 84 (accord, to Lagst.). Pleuros. acuminatum Grun. A. D. p. 56. V. H. Syn. 117 PI. 

 XXI f. 12. Per. VII f. 36, 37. Pleur. lacrustre W. Sm. B. D. I PL XXI f. 217. Fleur. trans- 

 sylvanicum Pant. Ill PI. VI f. 94? 



Fresh water: Sweden! England! Saxony! 



Var. curta G-run. (1880). — L. 0,o63 to O.ose; B. 0,oi45 mm. Ends subrostrate, obtuse. 

 Strise 18 in 0,oi mm. 



Fresh water: Holstein (Glrun.). 



Var. gallica GRtN. — V. sigmoid, lanceolate, with attenuate, subacute ends. L. O,oii to 

 0,15.^; B. 0,011 to 0,018 mm. Median line sigmoid, central. Longitudinal and transv. striffi equi- 

 distant 20 to 21 in 0,01 mm. — P. scalprum var. gallica Grun. V. H. T. N:o 172. P. gallic. 

 Per. VII f. 2. 



Fresh and brackish water: Sweden (Hernosand, fossil, Rimforsa i Vestergotland, Rings jon)! 

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



Var. Brebissonii Grun. (1880). — V. sigmoid, linear-lanceolate, with subacute ends. L. 0,0 8 6 

 to 0,104; B. 0,0 11 to 0,013 mm. Median line central, sigmoid. Transverse and longit. strise equi- 

 disstant, 22 to 23 in 0,oi mm. — Fleuros. halticum y W. Sm. B. D. XXII f. 207 y. P. Breb. Grun. 

 A. D. p. 56. Per. VII f. 29, 30? P. bait. var. Breb. V. H. Syn. p. 117 PI. XXI f. 6. P. scalp- 

 rum Rabh. A. Eur. N:o 2013 (accord, to Grun.). 



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



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

 obtuse ends. L. 0,4 to 0,45; B. 0,038 to 0,04i mm. Median line central, flexuose near the central 

 nodule, which is obliquely elongated. Transverse and longit. strise equidistant, 14 in 0,oi mm. — 

 Pletiros. Terr. Per. p. 18 PI. VII f. 21. 



Marine: Connecticut! 



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

 L. 0,08 to 0,13; B. 0,018 to 0,02i mm. Median line central, sigmoid. Central nodule large, 



