O’Mrara—Report on the Irish Diatomacee. 411 
Navicula heuflerit, (Grunow). Fresh water. 
Valve very small; lanceolate; central nodule large. Stric fine; 
linear, radiate; length about ‘0009, breadth about 0003. (Plate 
34. fig. 15.) 
Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band x., 1860, 
p. 528, T. i., fig. 32. Schumann, Diat. der Hohen Tatra., p. 68. 
Rab. Fl. Eur. Alg., sect. 1., p. 214. 
Lough Gill, Co. Kerry. Powerscourt, Co. Wicklow. 
Navicula fortis, (Gregory). Marine. 
Valve small; broadly lanceolate; rounded atends. Strie costate, 
convergent in the middle, radiate towards the ends; on front view, 
frustule slightly constricted, with the angles slightly rounded; length 
‘0017, breadth -0006. 
Malis. in: Pritch; p. 905.- Donkin, N. H.. Brit. Diat., p, 57, 
Pl. viii., fig. 8—Pinnularia fortis, Gregory, Q.J.M. S., Trans., 
1856, p. 47, Pl. v., fig. 19. Rab. Fl. Eur. Alg., sect.i., p. 215. 
Lough Gill, Co. Kerry. Arran Islands, Co. Galway. Malahide, 
Co. Dublin. 
Navicula northumbrica, (Donkin). Marine. 
Valve narrow, lanceolate; ends acute. Striz linear, convergent in 
middle, where they are strongly marked; length ‘0019, breadth 
0004. Frustule on front view slightly constricted. (Plate 384, 
ite, 16.) 
Henk, Orv. Mot tel, ps9 Pls ie. 5S NN. H. Britt Mat., 
poos, bl. yi... Rap. PC Kur. Als. sect. 1, p:175. 
Bannow, Co. Wexford. Salt ditches near the town of Galway. 
Navicula arenaria, (Donkin). Marine. 
Valve lanceolate, narrow; ends acute, produced and slightly 
constricted. Striz costate, convergent; length :0019, breadth -0004, 
Frustule on front view very slightly constricted. (Plate 34, fig. 17.) 
Donkin, Q. J. M.S., 1861, p. 10, Pl.1., fig. 9; N. H. Brit. Diat., 
p. 56, Pl. viu., fig. 5. Rab. Fl. Eur, Alg., sect. i., p. 177. 
Portmarnock, Co. Dublin. 
Nawvicula inflexa, (Gregory). Marine. 
Valve lanceolate; slightly depressed at the extremities. Strie 
costate, convergent; length -:0018, breadth -0004. (Plate 34% 
fig. 18.) 
Ralis, in Pritch., p. 905. Donkin, N. H. Brit. Diat., p. 54, 
R.I. A. PROC:, SER. II., VOL, II., SCIENCE. 2X 
