52 BRITISH DIATOMACE^. 



Freshwater. Lewes, Feb. 1851, ^. (Sm. Wraj, Mr. G. Smith. Guild- 

 ford, Mr. Capron. Var. /3. Lewes, April and October, 1852, and Feb. 1853, 

 W.Sm. 



Plate XVII. 147. Var. /3. PI. XVII. 147 /3. 



27. Navicula sphserophora, Kiltz. V. elliptical, constricted to- 

 wards the extremities, which are rounded and produced ; striae 

 very delicate, 42 in -001". Length -0022" to -0036". v.v. 



Kiitz. Bacill. iv. 17. Sp. Alg. p. 75. ad specim. quae misit amic. De Bre- 

 bisson. 



Freshwater. Lewes, Oct. 1851, W. Sm. Lough Mourae Deposit. 



Plate XVII. 148. 



28. Navicula angustata, n. sp. V. very narrow, elliptical, con- 

 tracted towards the rounded and produced extremities ; striae 45 

 in "001". Length -0016" to -0022". v.s. 



Fresh water. Killicrankie, Mr. P. Grant. Raasay Earth. 

 Plate XVII. 156. 



29. Navicula tumens, n. sp. F. V. inflated; V. elliptical, extre- 

 mities shghtly produced; strige interrupted, faint, 36 in '001". 

 Length -0025" to -0031". v.v. 



Brackish water. Newhaven, Sussex, Feb. 1852, W. Sm. 

 Plate XVII. 150. b. outline of F. V. 



30. Navicula punctulata, n. sp. V. oval, extremities scarcely pro- 

 duced ; striae distinct, 33 in "OOl", moniliform. Length "0016" to 

 •0032". v.v. 



Marine. Poole Bay, Sept. 1850, and Seaford, Sussex, Aug. 1851, W.Sm. 

 Plate XVI. 151. 



31. Navicula pusilla, n. sp. V. oval, extremities slightly produced ; 

 striae distinct, 26 in "001", radiating, punctate, v.v. 



Brackish water. Lewes, Oct. 1850, W. Sm. Near Belfast, Dr. Dickie. 

 Plate XVII. 145. 



