20 p. T. CLEVE, SYNOPSIS QF THE NAVICULOID DIATOMS. 



in 0,0 1 mm. more distant in the middle, where they are radiate and alternately longer and shoi"ter. 

 Terminal strise transverse. — Pant. II p. 51 PI. V f. 95. 

 Brackish water: Hungary, fossil! 



20. N. Wilczekii Gtrun. (1884). — V. elliptic-lanceolate, with protracted, rostrate ends. 

 L. 0,07; B. 0,026 mm. Axial area narrow. Central area subrectangular. Strife 10 in O.oi mm. 

 finely punctate, in the middle more distant (8 in 0,oi mm.) alternately longer and shorter, ra- 

 diate; strongly convergent at the ends, where they are closer (16 to 17 in 0,oi mm). — Franz 

 Jos. Land 1). p. 98 PI. I f. 3fi. 



Fresh water: Franz Josefs Land (Grun.). 



21. N. bottiiic.a Grun. (1880). — V. lanceolate, obtuse. L. 0,o4 to 0,o65; B. 0,oi to 0,oi3 

 mm. Axial area indistinct. Central area orbicular. Stride 20 in 0,oi mm. very finely punctate, 

 in the middle sti'ongly radiate and alternately longer and shorter, at the ends convergent. — 



A. D. p. 32 PI. II f. 32. V. H. Syn. PI. VII f. 33. 



Brackish and marine: Finmark! Coast of England! Baltic (from Pitea to Gothland)! Green- 

 land! Canada! Maine! 



22. N. digito-radiata Greg. (1856). — V. lanceolate, obtuse. L. 0,o6 to 0,o7; B. 0,oi2 to 

 0,0 18 mm. Axial area narrow. Central area small, irregular. Strire 9 in 0,0 1 mm., very finely 

 lineate, in the middle radiate and alternately longer and shorter, at the ends transverse. — Finn, 

 dig. M. J. IV PL I f. 32. N. dig. A. S. N. S. D. p. 92 PL III f. 4. V. H. Syn. p. 86 PL VII f. 4. 

 Tinnul. viridula Ehb. Abh. Berl. Ak. 1870 II f. 12. .A', dig. v. angustior Grun. A. D. PL II f. 31. 



Marine and brackish: Spitsbergen! Finmarken! Sea of Kara! North Sea! Saxony! Caspian 

 Sea (Grun.), Arctic America! New York! Fossil, Hungary (Grun.). 



Var. Cgprinus (Ehb. 1843?) W. Sm. (1853). — V. slightly gibbous in the middle. L. 0,0 6 

 to 0,08; B. 0,oi2.'i to 0,0275 mm. — Tinn. Cypr. Ehb. Am. I: 2 f. 7? W. Sm. B. D. I PL XVIII 

 f. 176. N. digito-r. var. Cypr. V. H. Syn. p. 86 PL VII f. 3. 



Marine: North Sea! England (W. Sm.), Belgium (V. H.). 



Var. Seychellensis Cl. — As the type. L. 0,04; B. 0,oi mm. Stria? 12 to 13 in 0,oi mm. 



Marine: Seychelles (V. H. Coll.)! 



Under the name N. Gurovii Pantocsek (III PL IV f. 58) has figured a form, which seems 

 to be a new species, akin to N. digito-radiata or N. peregrina. It is broadly, almost rhomboid, 

 lanceolate. L. 0,o6 5; B. 0,02 mm. Strise 6 in 0,oi mm. the median of unequal length. 



23. N. Reinhardtii Grun. (1860). — V. elliptical to lanceolate, with broad, obtuse ends. 

 L. 0,04 to 0,07; B. 0,0 14 to 0,0 17 mm. Axial area very narrow. Central area irregular, trans- 

 versely dilated. Stria; 9 in 0,oi mm., coarsely lineate, in the middle alternately longer and 

 shorter, strong!}^ radiate, in the ends transverse. — Sfaiironeis licinhardtii Grun. Verb. 1860 p. 566 

 PL VI f. 19. Nav. vernalis Donk. M. J. 1869 p. 293 PL XVIII f. 5. Nar. Beinh. V. H. Syn. 

 p. 86 PL VII f. 5, 6. Stanropfcra truncafa Rabh. Siissw. D. PL IX f. 12 (1853) Alg. Sachs. N:o 848. 



Fresh water: Sweden! England! Belgium (V. H.), Germany! Switzerland! 



Var. gracilior Grun. (1880). — V. lanceolate, narrowed towards the ends. L. 0,06 to 0,o7; 



B. 0,0 13 mm. Strite 8 to 9 in 0,oi mm. — N. digito-radiata var. strioJata Grun. A. D. p. 32. 

 N. Reinh. var. grucilior V. H. Syn. p. 87. 



Fresh water, occurring with the type. 



Var. jenisseyensis Grun. (1880). — As. var. gracilior, but with only few shorter median strife. 

 L. 0,132; B. 0,0 16 mm. A. D. p. 32. 



Fresh water: Mouth of Jenissey (Grun.). 



N. Reinhardtii is very similar to N. digito-radiata, from which it differs by its fresh water 

 habitat, and its more coarsely lineate strife, and to N. Gastrmn, which has striae radiate throughout. 



