344 Proceedings of the Royal Irish Academy. 
Navicula trevelyana, (Donkin.) Marine. 
Frustule on front view deeply constricted, with truncate extremi- 
ties; middle and end nodules apparent, with a narrow slightly lunate 
unstriate band at either side of the central nodule; valve linear, rounded 
at ends; length about °0048, breadth about -0008; median line some- 
what undulate; intermediate free space narrow, except around the 
median nodule, where it is much and roundly expanded; costz strong, 
converging in the middle, and radiate towards the ends. (Plate 30, 
fie. 9: 
pee Q:. J. M..8.; 1861, p/m, Pl. hese) eo. Nee 
Diat., p. 66, Pl. 10, fig. 6.—Pinnularia trevelyana, Rab. Fl. Eur. Alg. 
sect. 1... 210. 
Bannow, Co. Wexford. Malahide, Co. Dublin. 
Navicula oblonga, (Kiitz.) Fresh water. 
_ Frustules on front view quadrangular, narrow; valve narrow, 
elliptical; length about 0058, breadth about -0007; apices broad, 
rounded; coste strong, convergent; intermediate free space narrow, 
except in middle, where it is roundly expanded. (Pl. 30, fig. 10.) 
Kitz. ‘Bac., p. 97, @. iv., fis. 21. Raliso im Priteh., p. 907.9 Gin. 
now, Verhand. der K. K., Zool. Bot. Gesel, Band x., 1860, p. 528. 
Cleve, Om Svenska och Norska Diat., p. 225.—Pinnularia oblonga, 
Wm. Sm. B.D., Vol.i., p. 54, Pl. xvii., fig. 165. The form described 
by Rabenhorst, Siissw. Diat., p. 45, T. vi., fig. 6, as Pinnularia 
oblonga, is obviously different from the present species. 
Castlebridge, Co. Wexford. River near Glencar, Co. Kerry. 
Pond, Newcastle-Lyons, Co. Dublin. Powerscourt Demesne, Kilcool, 
Co. Wicklow. 
Nawicula oblonga, var. lanceolata, (Grunow.) Fresh water. 
Valve shorter and broader than in the typical form, lanceolate, 
with rounded ends; intermediate free space narrow. 
Grunow remarks that this variety ‘‘ stands near to Pinnularia pere- 
erina, as described by Wm. Smith,” but it is certaimly distinct, being 
found in localities beyond the reach of marine influence. It may 
be distinguished from Navicula peregrina by the intermediate free 
space, expanded in the middle, which that form does not exhibit. 
Grunow, Verhand. der K. K. Zool. Bot. Gesel., Band x., 1866, p. 
523, T. iv., fig. 25. 
Lough Mourne deposit, Co. Antrim. 
Navicula longa, (Gregory.) Marine. 
Valves lanceolate; length about ‘0060; breadth about -0010; 
coste strong, distant, slightly radiate in the middle, more radiate 
