92 p. T. CLEVE, SYNOPSIS OP THE NAVICULOID DIATOMS. 



Br. D. XVIII f. 163 /S. Nav. semicruciata A. S. Atl. XLIV f. 43? XLIII f. 24. Nav. viridis 

 var. comnudata V. H. S. p. 73 Pl.V f. 6. A. S. Atl. XLV f. 10, 11. 



Fresh water: Sweden (Lapland to Smaland)! Belgium (V. H.), Germany (Harz Atl.. Eis- 

 leben Atl.), Australia (Waltham Mass., Monticello, Sierra Famatina Argent., Eio Purus Brazil)! 



According to Van Hbukck's Syn. the valves of the same frustule are dissimilar, the striae 

 being in one uninterrupted and in the other unilaterally interrupted. This variety, confounded 

 with the preceding, is distinguished by its almost parallel striae. 



Var. semicruciata Grun. (1882). — V. large. Striae unilaterally interrupted. — Nav. viridis 

 var. semicruciata Gkun. Foss. D. Oster. Ung. p. 143. 



Fresh water: Hungary, foss, (Grun.). 



Var. rupestris Hantzsch (1861). — L. 0,04 to 0,o65; B. 0,oo7 to 0,oi2 mm. Area very 

 narrow. Striae 13 to 15 in 0,oi mm. divergent in the middle, convergent at the ends. — Pinnul. 

 rup. Hantzsch Eab. Alg. E. N:o 1203. Nav. rap. A. S.^ Atl. XLV f. 38 to 44. 



Fresh water: Sweden (Top of the mountain Areskutan! Vernamo, foss., Atl.), Norway! 

 Finland! Denmark (Ringkiobing, Atl.), Holstein! Iceland! Scotland (Braemar, Edinburgh, Loch 

 Canmor, Atl.), Saxony! America (Cherryfield)! Martinique! 



Var. dispar Schum. (1862). — Area unilateral. L. 0,05 to 0,o6 mm. Striae 7 in 0,oi mm. 

 — Nav. dis. Schum. P. D. 1 Nachtr. p. 189 f. 50. 



Fresh water: KSnigsberg, foss. (Schum.). , 



62. P. distingnenda Cl. (1891). — V. linear to elliptic-linear, with rounded ends. L. 0,io 

 to 0,18; B. 0,02 to 0,026 mm. Median line distinctly complex; central nodule large, excentric; 

 terminal iissures comma-like. Axial area broad, about 1/3 of the breadth of the valve, irregularly 

 linear-lanceolate, unilaterally widened in tbe middle. Striae 7 in 0,oi mm., strongly divergent in 

 the middle and convergent at the ends, crossed by indistinct bands. — Nav. viridis KtJTZ Bac. IV 

 f. 18. Pinnul. viridis W. Sm. f. 163 a. Pinnul. viridis var. distinguenda Cl. D. of Finl. p. 22 

 PI. I f. 1. Nav. Hyrtlii Pant. Ill PI. XVII f. 257 (1893)? Nav. viridis var. fossilis Pant. Ill 

 PI. XII f. 193 (1893). Nav. paripinnata Pant. Ill PL XVIII f. 263 (1893)? 



Brackish or fresh water: Sweden (Carlshamn and Sodertelge Depts.)! Finland! Hungary 

 (Bory Dept.)! Kamtschatka! Africa (Congo V. H. Coll.)! Australia (South Yarra, Tasmania)! New 

 Zealand! America (Houghton foss., Michigan Shasta Co. and S:ta Rosa Cal., "Washington Territory, 

 Sierra Famatina, Argent.)! 



63. P. gentilis Donk. (1873). — V. linear, with parallel margins and broadly rounded ends. 

 L. 0,14 to 0,25; B. 0,022 to 0,036 mm. Median line slightly complex, with somewhat approximate 

 central pores and comma-shaped terminal fissures. Axial area, narrow, less than 1/3 of the breadth 

 of the valve. Striae 7 in 0,oi mm., divergent in the middle, convergent at the ends, crossed by a 

 moderately broad, not very distinct, band. — Nav. gentilis Donk. Br. D. p. 69 PI. XII f. 1. A. S. 

 Atl. XLII f. 2. 



Fresh water: Sweden (Lapland to Upland)! Finland! England (Donk., Atl.), Schlesien 

 (Gronowitz foss.)! United States (Salem Mass., "Waltham Mass.)! 



64. P. nobilis Ehb. (1840). — V. linear, slightly gibbous in the middle and at the broadly 

 rounded ends. L. 0,25 to 0,35; B. 0,034 to 0,05 mm. Median line complex, with somewhat approxi- 

 mate central pores and comma-shaped terminal fissures. Axial area linear, less than 1/3 of the 

 breadth of the valve, slightly widened around the central nodule. Striae 4,5 to 5 in 0,oi mm. 

 divergent in the middle, convergent at the ends, crossed by a distinct band, '/j as broad as the 

 length of the striae. — Ber. 1840 p. 214. AV. Sm. Br. D. XVIII f. 161. P. mesogongyla Ehb. p. p. 

 M. G. VI: 1 f. 5. Nav. noiilis KtJTZ Bac. p. 98 PI. IV f. 24. Donk. Br. D. p. 68 PI. XI f. 1. 

 V. H. Syn. p. 73 PI. V f. 2. A. S. Atl. XLIII f. 1. 



