O'Meara — JRcport on the Irish Diatomacece. 365 



Navicula lineata, (Donkiu). Marine. 



Yalve linear, elliptical, with cuneate ends ; margin slightly 

 curved. Striae strong, convergent in the middle, and radiate towards 

 the ends ; longitudinal sulcus dividing the striae into two nearly eqiial 

 parts ; intermediate free space broad, lanceolate towards either 

 end, and expanded in the middle ; length about •0034, breadth 

 about -0010. (PI. 31, fig. 22). 



Donkin, Q. J. M. S., 1859, p. 32, PL iii., fig. 17. Also K H., 

 Brit. Diat., p. 8, PL i., fig. 8. 



Seashore near the town of Galway. 



Navicula liher, (Wm. Sm.) Marine. 



Valve narrow elliptical, with rounded ends. Strise 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.) 



Wm. Sm., B. D., Yol. L p. 48, PL xvi., fig. 133. Ealfs, ia 

 Pritch., p. 907. Grunow, Yerhand. der Zool. Bot. GeselL, Band x., 

 1860, p. 547. Cleve, Om Svenska och jSTorska Diat., p. 227. Eab. 

 ri. Eur. Alg., sect, i., p. 180. Donkin, N. H. Brit. Diat., p. 62, 

 PL ix., fig. 5. 



Salt ditch, near the town of "Wexford. Lough Gill, Co. Kerry. 

 Seaweeds, Kilkee, Co. Clare. Lough Poyle, near IS^ewtownlima- 

 vady, Co. Derry. Breaches, near JSTewcastle, Co. Wicklow. Galway 

 Bay. 



Navicula hicuneata, (Grunow). Marine. 



Yalve deeply constricted in the middle, with long cuneate ends, 

 somewhat rounded at the apex. Striae 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. (PL 31, fig. 24.) 



Grunow, Yerhand. der K. K. Zool. Bot. GeselL, Band x., 1860, 

 p. 546, T. iii., fig. 4. This author considers the form may be only a 

 variety of J^avicula liber, from which, however, it differs both in 

 form and structure. The striae in this are parallel, in jS^avicula 

 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 



2 S 2 



