184 p. T. PLEVE, SYNOPSIS OF THE NAVIOULOID DIATOMS. 



mum (i sessile KtJTZ. (fide Grrun.). G. Brebissonii KtJTZ. (fide Grrun.). G. mexicnnum Grun. in 

 V. H. Syn. PI. XXIV f. 3. G. Kitihcrianum Pant. Ill PI. X f. 162, 165. 



Presh water: Sweden! Finland! Holstein! Belgium (V. H.), France! England! Neusidler See 

 (Grun.), Iceland! Argentina! C'himborazo, Ecuador! Sandwich Islands! Tasmania! Auckland! California! 



Var. obliqua Grun. (1884). — Cyml>elloid bent, a.symraetrical to tlie longitudinal axis. — 

 Grun. Fr. Joseplis L. 1). p. (98)46. 



Var. acuminata H^rib. a. Pera(;. (1893). — Lanceolate, tapering towards the narrow ends, 



— G. subclav. var. acum. H:^rib. a. Perag. D. d'Auvergne p. 55 PI. Ill f. 8. 



Fresh water: Auvergne, fossil. 



Var. Mustela Ehb. (1854). — Biconstricted, with gibbous, obtuse apex. — G. Musi. Ehb. M. 

 G. PI. VII: 3, B. f. 9. ScHUM. P. D. p. 187 PI. IX f. 30. V. H. Syn. PI. XXIV f. 4 to 7. 

 G. Sac/if ta ScHUM. P. D. Ill Nachtr. PL II f. 16? 



Fresh water: Beeren Eiland (Lagst.), Finmark! Norway, Dovre! Finland! Gulf of Bothnia! 



Forma curvafa Br. a. Perag. (1893). — Frustules in front-view curved. — H^rib. D. d'Au- 

 vergne p. 59 PI. Ill f. 6, 7. 



Fresh water: Auvergne, fossil. 



Var. monfana Schum. (1867). — Biconstricted, with protracted snbtruncate or obtuse apex. 



— Schum. Tatra p. 67 PI. Ill f. 35. V. H. Syn. p. 124 PI. XXIII f. 33 to 36. 6;. anmmiafam 

 rar. siilmonfana Gutwinsky F1. Galiz. p. 28 PI. I f. 23. 



Fresh water: Galiz. (Schum.), Belgium (V. H.), Hungary, fossil ((xrun.), Demerara River! 

 G. subclavatum by its variety montana makes complete transition to G. ficnmiriafum, the 

 latter compi'ising forms with acute, tlie former with obtuse ends. 



11. G. Jieumiiiatiim Fhb. (1838). — V. clavate, more or less biconstricted, wath apiculate 

 apex, and narrow basis. L. O.os to 0,0?; B. 0,009 to 0,oi mm. Axial area narrow or indistinct; 

 central area short and narrow, unilateral. Stria; 10 to 11 in 0,0 1 mm., slightly radiate, the median 

 stria opposite to the stigma being shortened. — Ehb. Inf. p. 217 PI. XVIII f. 4. W. Sm. B. D. 

 I PI. XXVIII f. 238 a, a'. 



Forma trigonocephaJa Ehb. (1854). — V. not distinctly biconstricted. Apex cuneate. — 

 G. trig. Ehb. M. G. PI. VI: 1 f. 36. V. H. Syn. PI. XXITI f. 18. 



Forma Brebi.'^sonii KtJTZ. (1859). — V. slightly biconstricted, with cuneate apex. — G. Brf'b. 

 KtJTZ. Sp. Alg. p. 66. V. H. Syn. XXIII f. 23—26. C. ac. var. (Jlarus V. H. Syn. PI. XXIII 

 f. 20. G. acum. W. Sm. B. D. PI. XXVIII f. 238 a"'. 



Forma coronata. Ehb. (1840). — V. strongly biconstricted. with broad, apiculate apex. — 

 G. coron. Ehb. Abh. 1840 p. 211. G. acum. W. Sm. B. D. PI. XXVllI f. 238 ^. V. H. Syn. 

 p. 124 PI. XXIII f. 15. Petit Lac des Vosges f. 2. Strose Kliecken f. 16. G. acum. V. H. Syn. 

 PI. XXIII f. 16. G. acum. var. laticeps V. H. Syn. 1. c. f. 17. 



Forma pusilla Grun. (1880). — As the f. coron. but smaller. L. 0,oa; B. (),oo8 mm. — 

 Grarim. rar. pus. Grun. V. H. Syn. PI. XXIII f. 19. 



Fresh water: Spitzbergen (Lag.st.), Sweden! Finland! Belgium (V. H.), England, (Sm.), Ger- 

 many! Switzerland! France! Spain! Canada! Mas.^sachu.setts! Illinois! 



Var. clongata W. Sm. (1855). — V. slender, elongated, strongly gibbous in the middle and at 

 the apex. L. 0,o7 to 0,n; B. 0,012 to 0,oi7 mm. StricC 12 in 0,oi mm. coar.sely punctate; puncta 

 about 20 in O.oi mm. — G. elongat. W. Sm. Ann. N. Hist. 1855 p. 6 PI. I f. 4. B. D. II p. 99. 

 G. acum. rar. elong. V. H. Syn. PI. XXIII f. 22. G. Brebissonii Grfm. M. J. II PI. IV f. 13 

 (1854)? G. acum. var. intermedia Grun. in V. H. Syn. PI. XXIII f. 21. 



Fresh water: Scotland! Finland! Vosges! 



Var. Tiirris Ehb. (1843). — V. very slightly biconstricted with cuneate or apiculate apex. 

 L. 0,04 to 0,06; B. 0,0 1.-! mm. Stri* 10 to 11 in 0,01 mm. — G. Turris Ehb. Am. p. 128. M. G. 

 PI. XIV f. 70, 71. V. H. Syn. PI. XXIII f. 31. 



