O’Mrara—Report on the Irish Diatomacee. 365 
Navicula lineata, (Donkin). Marine. 
Valve linear, elliptical, with cuneate ends; margin slightly 
curved. Striz strong, convergent in the middle, and radiate towards 
the ends ; longitudinal sulcus dividing the striz into two nearly equal 
parts; intermediate free space broad, lanceolate towards either 
end, and expanded in the middle; length about ‘0084, breadth 
about -0010. (Pl. 31, fig. 22). 
= Donkm, Q. J: M: 8.}..1859)7 p. $2; Pl. m1., fig. 17. Also N. EL, 
Brit. Diat., p. 8, Pl.1., fig. 8. 
Seashore near the town of Galway. 
Navicula liber, (Wm. Sm.) Marine. 
Valve narrow elliptical, with rounded ends. Strie fine, slightly 
radiate, divided into two nearly equal portions by the longitudinal 
sulcus; intermediate free space narrow towards the ends; slightly 
expanded in the middle; length from ‘0030 to ‘0045, breadth 
from ‘0009 to 0012. (Pl. 31, fig. 23.) 
Want ism 3. Da. Vol: a2.pv 48, P)... xy.) fig.133;, Ralfs, m 
Pritch., p. 907. Grunow, Verhand. der Zool. Bot. Gesell., Band x., 
1860, p. 547. Cleve, Om Svenska och Norska Diat., p. 227. Rab. 
Hi, Eur..Alg> sect...1.;;p2.180...,-Donkin,, .N., H., Brit, Duiat.,,p.. 62, 
Phiaix., fig; 3. 
Salt ditch, near the town of Wexford. Lough Gill, Co. Kerry. 
Seaweeds, Kilkee, Co. Clare. Lough Foyle, near Newtownlima- 
vady, Co. Derry. Breaches, near Newcastle, Co. Wicklow. Galway 
Bay. 
Navicula bicuneata, (Grunow). Marine. 
Valve deeply constricted in the middle, with long cuneate ends, 
somewhat rounded at the apex. Striew linear, parallel; longitudinal 
sulcus nearer to the median line than to the margin; intermediate 
free space narrow, except in the middle, where it is slightly ex- 
panded; median line strongly developed; central nodule small, 
roundish; length -0056, breadth at the shoulders -0018, at the 
middle ‘0015. (PI. 31, fig. 24.) 
Grunow, Verhand. der K. K. Zool. Bot. Gesell., Band x., 1860, 
p. 546, T. ui., fig. 4. This author considers the form-may be only a 
variety of Navicula liber, from which, however, it differs both in 
form and structure. The strie in this are parallel, in Navicula 
liber slightly radiate. My specimens are generally wider at the 
shoulders, and more constricted than Grunow’s figure represents them. 
Cleve, Om Svenska och Norska Diat., p. 227, T. i., figs. 3 and 4. 
The form, as represented by this last-named author, is even less 
constricted than Grunow’s figure represents it. Cleve remarks :— 
‘‘Grunow has not described the front view, which in the specimens 
examined by me were cuneate, as is the case in Gomphonema 
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