O'Meara — Rejjo^'t on the Irish Diatomacece. 367 



PI. xvi., fig. 138. Smith's figure does not represent the longitudinal 

 striae, which more particularly characterize this species. Kiitzing's 

 figure, though representing this peculiarity, does not give to it its due 

 j)rominence. 



Drumoughty Lough, near Kenmare, Co. Cork. Marsh, Kilcool, 

 Glenmalure, Co. Wicklow. Lower Lake, Killarney, Co. Kerry. 

 Ditch, Cushendun, Co. Antrim. Pond in Botanic Grardens, Belfast. 

 Lough Mourne deposit, Co. Down. 



Var. ampMgomphus, (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. xxviii., fig. 40. Bab. Siissw. Diat'., p. 38, 

 T. vi., fig. 47. — JSTavicula firma, Balfs, in Pritch., p. 909. Donkin, 

 IS". H.Brit. Diat., p. 31, PL v., fig. 7. — Navicula firma, var. cuneata, 

 Lagerstedt, Sotv. Diat. fran Spetsbergen och Beeren Eiland, p. 29. 



Lower Lake, Killarney, Co. Kerry. Piperstown, Co. Dublin. 

 River Erne, near Crossdoney, Co. Cavan. Kilcool, Co. Wicklow. 



Var. affinis, (Ehr.) Eresh water. 



Valve like the typical species, but narrow and linear in outline ; 

 ends produced, broad, rounded, and sKghtly constricted. (Plate 31, 

 fig. 28.) 



ISTavicula afiinis, Kiitz. 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. Balfs, in Pritch., p. 902, PL xii., fig. 32. Rab. Siissw. 

 Diat., p. 40, T. vi., fig. 58. • Cleve, Om Svenska och Norska Diat., 

 p. 228. Donkin, JS". H. Brit. Diat., p. 33, PL v., fig. 8. Lagerstedt, 

 Sotv. 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.^ 



Navicida dulia, (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 ; striae in many specimens seen very slightly radiate ;: 

 length -0018, breadth -0008. (Plate 31, fig. 29.) 



Na\dcula dubia, Kiitz. Bac, p. 96, T. xxviii., 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, 

 in Pritch., p. 902. Donkin, N. H. Brit. Diat., p. 30, PL v., fig. 5.— 

 Navicula peisonis, Grunow, Verhand. der K. K., Zool. Bot. GeselL, 



