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



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



15. I 



large (L. 0,3 to 0.5 mm.) 18. 



, J Valve with gradually narrowed end.s G. Spenccrii W. 



■ I — — obliquely rounded — , 17. 



Length 0,06 mm ' G. sralproides Rabh. 



— 0,14 — , G. Tempei-ei Oi.. 



J Transverse striie about 9 in 0,0 1 mm G. Grovei Cl. 



I — — — 18 — G. sperfdhile Grun. 



I Median line sinuose G. i1ihn7iiiti(ni Grun. 



I — — not — 20. 



jj J Valve vorj' narrow. 17 or more times longer than broad G. Ihu-are Grun.. 



"I — less narrow 21. 



jj^ j Median line slightly excentric 22. 



'1 — — coincident with the margin 24. 



gj I Striae equidistant 23 



-2. <J 



Transverse striae wider than the longitudinal G. arctirnm Cl,. 



Striffi about 12 in 0,ni mm G. rohvfttum Grun. 



— — 20 — G. Wansherkii Donk. 



, j Frustule arcuate 2!^. 



-) 



not 2( 



I Valve Lr 

 20 



„. J Valve broad, unilaterally rounded G. conipactum Grey. 



I — narrow, lanceolate G. meditcrraiwiini Cl. 



) Transverse and longitudinal striie equidistant G. rectum Donk. 



{ 



— stria; narrower than the longitudinal G. nngiisfnt)! Donk. 



1. 0. acuniiiiatiim Kutz. (1S33). — V. sigmoid, lanceolate, gradually tapering to the obtuse 

 ends. L. 0,i to 0, is; B. 0,oi.5 to (),02 mm. Median line central, sigmoid. Transverse and longi- 

 tudinal stria; equidistant, about 18 in 0,oi mm. — Frusiitlia acuminata Kuxz. Linntea VIII p. 555 

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

 XXI f. 12. Per. VII f. 3(), 37. Pleur. lacrustre W. Sm. B. D. I PI. XXI f. 217. Fkur. trans- 

 syinanicum Pant. Ill PI, VI f. 94? 



Fresh water: Sweden! England! Saxony! 



Var. curfa Gtrun, (1880). — L. 0,oo:? to O.osf, ; B. 0,0 14.'') mm. Ends subrostrate, obtuse. 

 StriiE 18 in 0,oi mm. 



Fresh water: Holstein (Grun.). 



Var. (jallira Grun. — V. sigmoid, lanceolate, with attenuate, subacute ends. L. O.oii to 

 0, i.-).t; B. 0,0 11 to 0,0 18 mm. Median line sigmoid, central. Longitudinal and transv. striit' equi- 

 distant 20 to 21 in 0,0 1 mm. — P. scalprum rar. (jallica Grun. V. H. T. N:o 172. P. gallic. 

 Per. VII f, 2. 



Fre.sh and brackish water: Sweden (Hernosand, fossil, Rimforsa i Vestergotland, Ringsjon)! 

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



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

 to 0,104; B. 0,0 11 to 0,0 13 mm. Median line central, sigmoid. Transverse and longit. .stripe equi- 

 disstant. 22 to 23 in 0,oi mm. — Plcuros. halticum y W, Sm, B. I), XXII f, 207 y. P. Jireh. Grun. 

 A. D, p. 5G. Per. VII f. 29, 30? P. halt. var. Breh. V. H. Syn. p. 117 PI. XXI f. G. P. scalp- 

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



Fresh or slightly brackish water: Spitzbei'gen ! Sweden! Paris! Saxony! Argentina! 



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

 obtuse ends. L. 0.4 to 0,4 ri; B. 0,(i:!8 to 0,o4i mm. Median line central, flexuose near the central 

 nodule, which is obli(iixely elongated. Transverse and longit. .stritc ecjuidistant, 14 in 0,oi mm. — 

 Plmros. 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 0,1 a; B. 0.O18 to 0,02 1 mm. Median line central, sigmoid. Central nodule large, 



