O’Mrara—Report on the Irish Diatomacee. 367 
Pl. xvi., fig. 188. Smith’s figure does not represent the longitudinal 
stria, which more particularly characterize this species. Kiitzing’s 
figure, though representing this peculiarity, does not give to it its due 
prominence. 
Drumoughty Lough, near Kenmare, Co. Cork. Marsh, Kilcool, 
Glenmalure, Co. Wicklow. Lower Lake, Killarney, Co. Kerry. 
Ditch, Cushendun, Co. Antrim. Pond in Botanic Gardens, Belfast. 
Lough Mourne deposit, Co. Down. 
Var. amphigomphus, (Ehr.) Fresh water. 
Like the typical form in its general characters, but linear in its 
outline and cuneate at the ends; length from -0025 to :0045, breadth 
from -0010 to -0016. (Plate 31, fig. 27.) 
Kiitz. Bac., p. 93, T. xxviu., fig. 40. Rab. Siissw. Diat., p. 38, 
T. vi., fig. 47.—Navicula firma, Ralfs, in Pritch., p. 909. Donkin, 
N. H. Brit. Diat., p. 31, Pl. v., fig. 7.—Navicula firma, var. cuneata, 
Lagerstedt, Sotv. Diat. fran Spetsbergen och Beeren Hiland, p. 29. 
Lower Lake, Killarney, Co. Kerry. Piperstown, Co. Dublin. 
River Erne, near Crossdoney, Co. Cavan. Kailcool, Co. Wicklow. 
Var. afinis, (Ehr.) Fresh water. 
Valve like the typical species, but narrow and linear in outline ; 
ends produced, broad, rounded, and slightly constricted. (Plate 31, 
fig. 28.) 
Navicula affinis, Kitz. Bac., p. 95, T. xxviii., fig. 65, who attri- 
butes the species to Ehrenberg. Wm. Sm., B.D., Vol. i., p. 50, Pl. 
xvi., fig. 143. Ralfs, in Fritch., p. 902, Pl. xii., fig. 32. Rab. Stissw. 
Diat., p. 40, T. vi., fig. 58. Cleve, Om Svenska och Norska Diat., 
p. 228. Donkin, N.H. Brit. Diat., p. 33, Pl. v., fig. 8. - Lagerstedt, 
Soty. Diat. fran Spetsbergen och Beeren Eiland, p. 29. 
River Erne, near Crossdoney, Co. Cavan. Drumoughty Lough, 
near Kenmare, Glengarriff, Co. Cork. Bellarena, Co. Derry. Pond, 
Botanic Gardens, Belfast, Co. Down. Near Newcastle, Kilcool, 
Lugnaquilla mountain, Co. Wicklow. Killakee, Co. Dublin. 
Navicula dubia, (Ehr.) Fresh water. 
Valve like that of Navicula iridis, var. amphigomphus, but much 
smaller and broader in proportion; the cuneate ends extended into 
short apices; stris in many specimens seen very slightly radiate ; 
length -0018, breadth -0008. (Plate 31, fig. 29.) 
Navicula dubia, Kitz. Bac., p. 96, T. xxviil., fig. 61, who attri- 
butes the species to Ehrenberg. Rab. Siissw. Diat., p. 40, T. vi., fig. 
60. This latter figure is quite unlike the present species. Ralfs, 
im Pritch., p. 902. Donkin, N. H. Brit. Diat., p. 30, Pl. v., fig. 5.— 
Navicula peisonis, Grunow, Verhand. der K. K., Zool. Bot. Gesell., 
