'I 

 I 



3 to 4 times longer than broad 



4 to 6 — — — — 



^°- > 6 to 7 



14 p. T. CLEVK, SYNOPSIS OF THE NAVICULOID DIATOMS. 



„ . . Habitat: fresh-water . . ... . . N. gracilis Ehb. 



marine . 95. 



96. 



N. transitans Cl. 

 N. Zostereti Gbtin. 



10 _ _ _ — . . . . . N. directa W. Sm. 



„„ I Valve rhomboidal . .... . . N. superha Cl. 



\ — lanceolate . . . . . N. gelida Gbun. 



f Striae between the margin and the axis faint 98. 



97. < — unilaterally crossed by an area . ... . 99. 



I — crossed by undulating, blank bands . 100. 



„„ J Central nodule a short stauros iV. finmarchica Cl. a. Geun. 



■ \ — — not stauroid . . . . N. transitans v. derasa (N. kariana v. detersa). 



Q„ ( Valve about 10 times longer than broad . . N- directa v. Incus. 



' \ — — • 5 to 6 — — — ,. N. transitans v. incudiformis. ' 



inn I Valve very convex . . . . . . . 101. 



100- j _ ijot - loa. 



..-^ j Valve fusiform . N. vitriscala Brtjn. 



\ — linear N. mediterranea Ba. a. Cl. 



109 i ^^'^^ linear with cuneate ends . N. trigonocephala Cl. 



\ — lanceolate . . . N. transitans v. erosa. 



^„„ f Llneation oblique . . N. Kepesii Gbun. 



I — straight . ... 104. 



^fv.. f Valve narrow lanceolate N. ramosissima Ag. 



104. I 



broadly — . . . . . N. Kariana Gbun. 



1. N. cryptocephala Kutz. (1844). — V. lanceolate, with rostrate-capitate ends. L. 0,o25 

 to 0,035; B. 0,005 to 0,007 mm. Axial area indistinct. Central area small, somewhat transverse. 

 Strife 16 to 18 in 0,oi mm., radiate in the middle, slightly convergent in the ends, finely lineate. 

 — Bac. p. 95 PL III f. 26. Donk. B. D. p. 37 PL V f. 14. V. H. Syn. p. 84 PL VIII f. 1, 5. 

 Nav. mutica Rabh. Alg. Sachs. N:o 965. 



Fresh water: Sweden! England! Belgium (V. H.), Grermany! France! Arctic America! Green- 

 land! Argentina! Japan! 



Var. veneta Kutz. (1844). — Smaller, with scarcely capitate ends. L. 0,025; B. 0,oo5 mm. 

 StriEe 14 in 0,oi mm. — N. veneta KtJTZ. Bac. p. 95 PL XXX f. 76. Pedicino Ischia PL II f. 9 

 to 12? DoNK. B. D. p. 43 PL VI f. 13? N. crypt, v. veneta V. H. Syn. p. 85 PL VIII f. 3, 4, 

 PL XIV f. 34. 



Brackish water: Sweden, Malmo! Venice (Kutz). 



Var. pumila Grun. (1880). — V. rhombic-lanceolate. L. 0,oi6 to 0,023; B. 0,oo6 to 0,oo7 

 mm. Strise about 15 in 0,oi mm. — V H. Syn. PL VIII f. 6, 7, XIV f. 35. N. BJwmbulus 

 ScHUM. P. D. II N. p. 56, PL II f. 35 (1867)? N. Lancettula Schum. P. D. II N. PL II f. 34. 

 N. cryptoc. v. Lancettula V. H. Syn. PL VIII f. 11. N. pumila v. fossilis Pant. Ill PL V f. 75 (1893)? 



Brackisch water: Triest! 



Var. perminuta Grun. (1880). — V. lanceolate, not capitate. L. 0,oo8 toO,oii; B. 0,oo3 mm. 

 Strife about 20 in 0,oi mm. — V. H. Syn. PL XIV f. 7. 



Var. exilis Kutz (1844 p. p. accord, to Grunow). — V. lanceolate, with subrostrate, obtuse 

 ends. L. 0,oi8 to 0,oi9; B. 0,oo5 mm. Strife about 19 in 0,oi mm. — V. H. Syn. p. 85 PL VIII f. 2, 4. 



Fresh water: Belgium (V. H.), Somme! Triest! 



2. N. gotlandica Geun. (1878). — V. narrow, lanceolate, with protracted, subacute ends. 

 L. 0,05 to 0,06; B. 0,oo8 mm. Axial area indistinct; central area small, orbicular. Stride 14 

 (middle) to 18 (ends) in 0,oi mm. radiate in the middle, convergent in the ends. — Cl. M D 

 N:o 161. V. H. Syn. PL VIII f. 8. 



Slightly brackish water: Sweden, Gothland! Tasmania! 



' jV. irregularis Pant. N. superha v. elliptica. 



