> ‘i l
Freshwater. Lewes, Feb. 1851, IF. &«. Yimj, 3Ir. G. Smith. Guildford,
Mr. Capron. Var. (3. Lewes, April and October, 1852, and Feb. 1853,
IF. Sm.
Plate XVII. 147. AAar. ¡3. PI. XVII. 147 ¡3.
27. Navicula sphserophora, Kiitz. V. elliptical, constricted towards
the extremities, which are rounded and produced; striæ
very delicate, 42 in ’OOl". Length -0022" to '0036". v.v.
Kütz. Bacill. iv. 17. Sp. Alg. p. 75. ad specim. quæ misit amie. De Bré-
bissoii.
Freshwater. Lewes, Oct. 1851, IF. Sm. Lough Mourne Deposit.
Plate XAHI. 148.
32. Navicula tumida, n. sp. V. elliptical, contracted at the extremities,
which are rounded and produced ; striæ very distinct,
24 in -001", reaching central line, punctate and radiate, v.s.
Fresh water. Bramley near Guildford, Mr. Capron, Nov. 1850.
Plate XVII. 146.
33. Navicula dicephala, Kiitz. V. linear, constricted towards the
rounded extremities ; striæ distinct, 26 in -OOl", radiate, v.s.
Kütz. Bacill. xxviii. 60 ?
Fresh water. Guildford, Mr. Capron. Lough Mourne Deposit.
Plate XVII. 157.
28. Navicula angustata, n. sp. V. very narrow', elliptical, contracted
towards the rounded and produced extremities ; striæ 45
in -001". Length -0016" to -0022". v.s.
Fresh water. Killicrankie, 3Ir. P. Grant. Raasay Earth.
Plate XAHI. 156.
34. Navicula cryptocephala, Kütz. V. minute, constricted towards
the ohtuse extremities; striæ faint, 56 in ’OOl". v.v.
Kütz. Bacill. iii. 20 & 26.
Freshwater streams. Corfe Castle, Dec. 1849, IF. Sm. Belfast, Dr. Dickie.
Plate XVII. 155.
29. Navicula tumens, n.sp. F .V . inflated; V. elliptical, extremities
slightly produced; striæ interrupted, faint, 36 in -OOl".
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 produced
; striæ distinct, 33 in '001", 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 ;
striæ distinct, 26 in •OOl", radiating, punctate, v.v.
Brackish water. Lewes, Oct. 1850, W. Sm. Near Belfast, Dr. Dickie.
Plate XVII. 145.
Sec t . VI. Valves with a central constriction.
3 5 . Navicula didyma, Kütz. V . elliptical, more or less deeply constricted
in the centre; striæ interrupted, distinct, 24 in •OOl".
Length -0014" to -0032". v.v.
Kütz. Bacill. IV. 7. xxviii. 75. Navicula interrupta, Kütz. Bacill. xxLx. 93.
Pinnularia Apis, Ehr. in Kiitz. Bacill. xxviii. 76.
Marine : very common. Sussex, July 1850, IF. Sm. (New Zealand.)
Plate XVII. 154. a. and a', ordinary forms ; b. outline of ditto in S. D. ;
a*, var. (Sporangial?) from Skye, Prof. Williamson. Frustule with endochrome,
Frontispiece, fig. CLIV.
3 6 . Navicula binodis, Ehr. V. constricted in the centre, extremities
slightly produced ; striæ obscure, v.s.
Kiitz. Bacill. iii. 35.
Fresh water. Lewes, Aug. 1850, IF. Sm. »
Plate XVII. 159.