O’Mrara—Report on the Irish Diatomacee. 381 
latter, I presume, to be the present one. Ralfs, (in Pritch., p. 903), 
says the only species with which this could be confounded is 
Navicula firma, but it appears to me that it is more likely to be 
confounded with Navicula punctata. Rab. Fl. Eur. Alg., sect.i., 
p. 200. 
Lough Mask, near Tourmakeady, Co. Mayo. Lough Neagh, near 
the town of Antrim. Lough Gill, Lower Lake, Killarney, Pedlass 
Lake, near Dingle, Co. Kerry. 
Navicula maculosa, (Donkin). Marine. 
Valve linear, elliptical; ends slightly produced and somewhat 
cuneate; intermediate free space linear, narrow, slightly expanded 
around the central nodule; striz distinctly moniliform, parallel in 
the middle, and divergently radiate towards the ends; length ‘0027, 
breadth -0008. (Plate 32, fig. 12.) 
Donkm, N: 1. Brt.,Diat.,.p. 25, Pl. y. fig. t. 
Piles of wooden bridge, Dollymount Strand, Co. Dublin. 
Navicula scutelloides, (Wm. Sm.) Fresh water. 
Valve nearly orbicular, minute; intermediate free space narrow, 
linear, slightly expanded in the middle; strie distant, moniliform, 
divergently radiate ; length, 0009; breadth, 0008. (Plate 32, fig. 13.) 
Wm. Sm., B. D., Vol. ., p. 91. Grunow, (Verhand. der K. K. 
Zool. Bot. Gesell., Band x., 1860, p. 533, T. v., fig. 15), places it in 
intimate connexion with Navicula lyra and Navicula hennedyi, but the 
position I assign to it seems to me more appropriate. Rafls, in Pritch., 
p..909. Rab. Fl. Eur. Alg., sect.i., p..185. 
Lough Neagh, near Antrim. Lough Mask, near Tourmakeady, 
Co Mayo.: 
Navicula pusilla, (Wm. 8m.) Brackish water. 
Valve small, broadly elliptical, ends produced; narrow, rounded; 
intermediate free space narrow, linear, expanded in the middle; strie 
distinctly moniliform; convergent in the middle, and radiate towards 
the ends; more distant in the middle, closer towards the ends ; 
length :0015; breadth, -0008. (Plate 32, fig. 14.) 
Wan ome te Nek es pe od, Pl; xvi, fic. 145." “Ralfs; im 
Pritch., p. 900. Cleve, Om Svenska och Norska Diat., p. 227. Itis 
likely that the form mentioned by Cleve may be a distinct species, as 
he attributes it to fresh water. Rab. Fl. Eur. sect. 1., p. 193. 
Donkin, N. H. Brit. Diat., p. 20, Pl. iu., fig. 6—Navicula tumida, 
var. subsalsa, Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band 
x., 1860, p. 537, T. iv., fig. 43. 
Brackish ditch near town of Wexford; Tacumshane, Co. Wexford. 
Ballysodare, Co. Sligo. Breaches near Newcastle, Co. Wicklow. 
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