80 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. - 



20. P. Hartleyana GtREV. (18(i5). — V. linear, gibbons in the middle and at the ends. 

 L. 0,2 to <»,23; B. 0,03.3 to 0,045 mm. Median line straight, filiform. Axial area linear, less than 

 '/., as broad as the valve, in the middle transversely dilated, freqnently to a fascia. Striie S in 

 0,0 1 mm. divergent in the middle, convergent at the ends. — T. M. S. vol. XIII PI. VI f. 30. 



Fresh water: Liberia (Grrev.), Demerara River! 



21. P. episcopalis Cl. (1891). — V. linear, with parallel margins and broad ronnded ends. 

 L. 0,23 to 0,36; B. 0,035 to 0,04 mm. Median line filiform with comma-like terminal fissures. 

 Axial area broad, abont ^'^ of the breadth of the valve, in the middle widened to a transverse 

 fascia. Stria; 8 in 0,oi mm., strongly divergent in the middle and convergent at the ends. ■ — 

 F. cardinalis Ehb. M. G. XVIII: I f. 4. P. episcopalis Cl. D. of Finl. p. 27 PI. I f. 4. 



Fresh water: Sweden (Lake Wenern, Lake Rosslangen in Kalmar Ian, Ojasjo Dept. in Ble- 

 kinge, interglacial mud from Hernosand)! Finland! Lac CTerardnier, Vosges! Cherryfield, America! 



Var. hrcris Cl. — L. 0,i8; B. 0,o38 mm. Striai fi in 0,oi mm. less radiate. 



Fresh water: New Zealand (Au('kland, Witt Coll.)! 



Var. africana Cl. — V. smaller. L. 0,ii5; B. 0,oi8 mm. Axial area less tlian a third of 

 the breadth of the valve. Striai 8 in 0,01 mm. 



Fresh water, mouth of rivers: Cameroon, Africa! 



P. cpiscopaJis is a very large and beautiful diatom, neaily akin to F. iliveryi'ns and to 

 F. H<(ith'!/ana. 



IV. Distantes. 



M 



Arfifieial key. 



Valve lanceolate P. alpina W. Sm. 



more or less narrow, elliptieal 2. 



jj I Very small forms. L. abont 0,oi mm P Balfouriana Grun. 



1 Length 0,oa to 0,i mm. and more 3. 



j L. 0,1 mm. and more P. lata Br^b. 



I L. less than 0,i mm , . . 4. 



•. ;;■ ■ ^ j Stria f) to 6 in 0,oi mm. "." . .'[, ,7 ., , P. horealis Ehb. 



■ I — 8 in 0,01 mm P. intermedia Lagst. 



22. P. intermedia L.aust. (1873). — V. linear-elliptical, with rounded ends. L. 0,oi8 to 

 0,042; B. 0,06 to 0,08 mm. Axial area narrow; central a transverse fascia. Stria; radiate at the 

 ends, 8 in 0,oi mm. — Nar. int. L,4gst. Spetsb. 1). 23 PI. I f. 3. 



Fresh water: Spitsbergen (Lagst.), Beeren Eiland (Lag.st.). Anstralia (Blue Mountains)! 

 ' This form seems, according to Lagerstedt, to graduate into F. bonali.s and F. Brebissonii. 



23. P. Balfouriana (tRUN. Ms. — V. elliptical. L. 0,oi)s< to O.oi; B. o,o(n mm. Area wide. 

 Stria; distant, 10 in 0,oi mm. — PI. I f. 18. 



Fre.sh water: Scotland (Grun.), North Iceland! 



24. P. borealis Ehb. (1843). — V. linear-elliptical, with rour.ded or snbtruncate ends. L. 

 0,03 to O,ofi ; B. 0,007 to 0,uo8 mm. Median line with approximate central pores and hook-.shaped 

 terminal fissures. Area narrow Stria; parallel, 5 to 6 in 0,oi mm. — Am. PI. I: 2 f. (1. Nor. ho- 

 realis KtJTz B. p. 96. Grun. Verh. 18(50 p. 518. Lagst. Sp. D. PI. I f. 4. A. S. Atl. PI. XLV 

 f. 15—21. V. H. Syn. p. 76 PI. VI f. 3, 4. Wolle PI. IX f. 23. Pinnul. hehridensis Greg. M. J. 

 1854 p. 28 PL IV f. 13. Finn. ehiJensis Rabh. Alg. Sachs. 885 (1859). 



On mosses, moist earth, in fresh water: Spitsbergen! Beeren Eiland (Lagst.), (xreenland! 

 Iceland! Sweden! Finland! Germany! Englaiul! Belgium (V. H.), Switzerland! Japan! S:t Pauls 

 Island (Grun.), Sandwich Islands! Australia (Blue Mountains)! New Zealand! South Africa! 

 Argentina! Ecuador! "\V. Ind. S:t Vincent! 



