.54 1'. T. clevp:, synopsis ov the n.wiculoid diatoms. 



each side of the median line. Striiu slightly radiate in the middle, elsewhere parallel, 10 in 0,01 

 mm. — Nav. Kain. Pant. Ill PI. Ill f, 41. " 

 Habitat?: »Kopecz» (Pant.). 



17. €. obtlisa W. Sm. (1853). — V. very convex, subrectangular, with broad, truncate ends. 

 L. 0,05 to 0,06; B. 0,1)16 to 0,0 17 mm. Axial and central areas united in a moderately broad 

 lanceolate space, in the middle of which is on each side of the central nfidule a lunate marking 

 Strife 17 in 0,oi mm. parallel or slightly divergent towards the ends. Longitudinal lines sub- 

 marginal. ~ Nav. ohtiisa W. Sm. B. D. I p. 50 PI. XVI f. 140 (1853). (tKUn. Verli. ISijO p. 536 

 PL IV f. 39? N. Hchcs Ralfs Priteh. Inf. p. 896 (1861). Donk. B. D. p. 23 PL III f. 12. 



Fresh water, especially in nothern regions. (Ireenland! Sweden, Lappland and (xotland! 

 Russian Lappland! Norway, Dovre! Scotland! 



This species is very characteristic and not closely akin to any known form. It seems to 

 be an inhabitant of northern regions and is not mentioned by Brun as occuring in Switzerland, 

 nor by Belloc as occuring in the Pyrenees. 



18. C. Liber W. Sm. (1853). ■ — V. linear, sometimes with slightly concave or convex 

 margins, and rounded or subcuneate ends. L. 0,o5 to 0,19; B. 0,oo8 to 0,032 mm. Axial area in- 

 distinct or very narrow. Central area indistinct or small. Stri;i' 13 to 20 in 0,oi mm. parallel, 

 divergent at the ends. Longitudinal lines median, single or double. 



A. Forms with linear, sometimes slightly constricted valves, and without lunate markings 

 in the central area. 



a) LotKj'dudinal lines single. 



Var. linearis (tRUN. (1860). — V. narrow, linear, with jiarallel margins and rounded ends. 

 L. 0,054 to 0,12; B. 0,008 to 0,01 i mm. Areas indistinct. Strife 20 to 29 in 0,oi mm. Longitu- 

 dinal lines median, frequently indistinct. - Nav. linearis Grun. Verb. I860 p. 546 PL III f. 2. 

 V. H. Syn. p. 105 PL XII f. 35. A. S. Atl. L. f. 38, 40. 



Marine: Atlantic coasts of Europe, Africa and America (CtRUN.), Ceylon! Singapore (Brun 

 Coll.!) Galapagos Islands! Peru ((tRUN.), Honduras (Grun.), (julf of Mexico (Atl.). 



Var. genuina Cl. — V. linear, with parallel or slightly convex margins and more or less 

 broad ends. L. 0,o8 to 0,17; B. 0,oi3 to 0,o24 mm. Axial area very narrow; central area small, 

 orbicular, frequently somewhat asymmetrical. Striae 13 to 20 in 0,oi mm. — Nav. Lihrr W. Sm. 

 B. D. I p. 48 PL XVI f. 133. Lonk. B. D. p. 62 PL IX f. 5. A. S. Atl. L. f. 16, 17, 18. A. S. 

 N. S. D. II f. 45. V. H. Syn. p. 104 PL XII f. 36. Nav. maxima Greg. M. J. IV PL V f. 2 

 (1856). D. of CL p. 487 PL IX f. 18. A. S. Atl. L. f. 19 to 21, 37. N. S. D. II f. 44. Nav. 

 fortunata Lend. Fortm. D. de Ceylan PL III f. 27 (1879). 



Marine: Greenland! Spitsbergen! Finmark! Behrings' Island! North Sea! Mediterranean 

 Sea! Red Sea! Seychelles! Cape of (xood Hope! Ceylon! Singapore! Sidney! Port Jackson! Tas- 

 mania! Philippines! Japan! Campeachy Bay! 



Forma tenuistriata Cl. — L. 0,o65 to 0,07; B. 0,oi5 mm. Stride 25 to 26 in O.ui. 



Marine: Labuan! Sandwichs Islands! 



Forma convexa Cl. — Convex. L. 0,ii to 0, 13; B. 0,012 mm. Axial area somewhat broader. 

 Strife 16 to 20 in 0,oi mm. — Nav. Hauelm Cl. N. R. D. p. 9 PL II f. 27 (1881). 



Marine: Gulf of Naples! Adriatic! 



Vai'. Holnboi Pant. (1886). — V. linear, with rostrate capitate ends. L. 0,i 59 ; B. 0,025 mm. 

 Strife 20 in 0,oi mm. — Nav. {maxima var.?) Hoi. Pant. I p. 25 PL XVIII f. 165. 



Marine: Hnngary, fossil (Pant.). 



Var. relegata Cl. — V. slightly constricted in the middle, with cuneate ends. L. 0,15; B- 

 0,025 mm. Axial area linear-lanceolate. Stria; 12 to 13 in 0,oi mm., crossed by a median longi- 

 tudinal line. 



Marine: Redondo, Calif, fossil (Grove Coll.)! 



