394 Transactions of the Society. 



XIV. — 0)1 some Neiv Species of Nitzschia* 

 By A. Geunow, Hon. F.R.M.S. 



CBead 14th April, 1880.) 

 Plates XII. and XIII. 



Nitzschia, Sectio Pseudoteyblionella. 



N. Bahenlwrstii Grun., in Cleve and Grrunow, 'Arct. Diat.' — 

 Large, valves linear, with cuneate obtuse ends. Carinal puncta 

 forming very short striae 8-9 in O'Ol mm.; transverse striae 

 monihform, 17 in 0"01 mm. Valve with very short longitudinal 

 furrows. Length, 0*21-0 -25 mm.; breadth, 0-02-0 '021 mm. 

 Calcutta, in salt lakes {leg. Kurz). Plate XII. Fig. 1, ^°-. 



N. Graeffii Grun. I. c.\ — Large, valve broad linear, with shallow 

 longitudinal furrows, obsoletely constricted in the middle, cuneate 

 or rounded ends. Carinal puncta forming short striae 5-6 in 

 01 mm.; transverse striae moniliform, 11-12 in 0*01 mm. 

 Length, 0-145-0-21 mm.; breadth of valve, 0-027-0 '33 mm. 

 Seychelle Islands {leg. Dr. E. Graeffe). Plate XII. Fig. 4. The 

 narrow forms resemble N. Bahenhorstii, but differ in having more 

 distant carinal puncta and coarser striae. [This species is somewhat 

 widely distributed, I have seen it in gatherings from Colon, Jamaica, 

 Pisagua, Bahia, and Barbadoes. — F. K.] 



N. Nicobarica Grun. I. c. {N. fancluriformis var. Nicoharica 

 Grun., No vara Exp., T. la, fig. 4). — Carinal puncta large, semi- 

 circular, 2-3 in 0-01 mm. ; striae moniliform, 21-24 in * 01 mm. 

 Longitudinal furrows very conspicuous. Length, • 09-0 * 20 mm. ; 



EXPLANATION OF PLATES XII. AND XIII. 



All tlie figures are drawn to a scale of 900 diameters. The line a — b in some 

 figures separates the parts of the diatom when seen under a higher or a lower 

 power. 



Plate XII. 



Fig. 1. — Nitzschia Bahenhorstii Grun. 

 „ 2. — „ Nicobarica 



3. — ,, scaliijera 

 4. — „ Graeffii 



5. — a, b „ cocconeiformis 

 6. — „ perversa 

 7. — „ granulata 

 8. — Hantschia Amphyoxys 



var. amphilcpta 

 9. — Nitschia ainphicephala 



Plate XIII. 



Fig. 10. — Nitzschia limicola Grun. 



„ 11. — Gomphonitzschia Clevci „ 

 „ 12. — a, 6, c, N. Senegalensis „ 

 ,, 13. — Hantschia Wittii „ 



„ 14:. — Nitzschia Janischii „ 



(fl, central pseudo-nodule) 

 „ 15. — Nitzschia Febigeri „ 



„ 16. — a, b „ Campechiana „ 

 „ 17. — Gomphonitzschia Ungeri „ 



* Notes by Mr. F. Kitton, Hon. F.R.M.S. 



t This species is described and figured by Prof. P. T. Cleve iu the ' Bihapg 

 till K. Svenska vet. Akad. Handlingar,' No. 8. — F. K. 



