O'Meara — Report on the Irish Diatomacece. 407 



I f Radiosce. Stria more or less distinctly radiate. 



Navicxda radiosa, (Kiitz.) Presh. water. 



Yalve lanceolate, obtuse ; striae strongly costate ; convergent in 

 middle, radiate towards the ends ; length about '0020, breadth about 

 •0005. (Plate 34, fig. 3.) 



Kiitz. Bac, p. 91, T. iv., fig. 23. Ralfs, in Pritch., p. 905. 

 Grunow, Yerhancl. derK. K. Zool. Bot. Gresell., Band x., 1860. Cleve, 

 Om Svenska och jSTorska Diat., p. 225. Lagerstedt, Sotv. Diat. fran 

 Spitzbergen och Beeren Eiland, p. 25. — Pinnularia radiosa, ~Wm. 

 Sni. B. D., Yol. i., p. 56, PI. xviii., fig, 173. Rab. PI. Eur., Alg., 

 sect, i., p. 214. 



Pool, Glengariff, Co. Cork. Lower Lake, Killarney, Co. Kerry. 

 Stream Crossdoney, Co. Cavan. Piver Dodder, Bohernabreena, Glenas- 

 mole, Killakee, Co. Dublin. Lake near Castlewellan, Co. Down. 



Namcula gracilis, (Ehr.) Freshwater. 



Yalve lanceolate, attenuated towards the ends, which are obviously 

 produced ; strias costate, convergent in the middle, radiate towards 

 the ends ; length about -0022, breadth about -0005. (Plate 34, fig. 4.) 



Kiitz., Bac, p. 91, T. iii., fig. 48, T. xxx., fig. 57, who regards 

 the species described by him as identical with ISTavicula gracilis, Ehren- 

 berg, Infus., 1838, p. 176, T. xiii., fig. 2. Smith is doubtful as to 

 the identity of the form described and figured by him with that of 

 Kiitzing just referred to and comparison of the figures of Kiitzing 

 with specimens of the form, so accurately delineated by Smith will 

 impress* something more than doubt upon the observer's mind. Palfs, 

 in Pritch., p. 906. Grunow, Yerhancl. der K. K. Zool. Bot. Gesell., 

 Band x., 1860, p. 526, T. iv., fig. 27. The species is broader, more 

 attenuated at the ends, than this figure represents it. Schumann, Diat., 

 der Hohen Tatra, p. 69. Pab. PL Eur., Alg., sect, i., p. 174. — Pin- 

 nularia gracilis, Wm. Smith, B. D., Yol. i., p. 57, PI. xviii., fig. 

 174. 



Drumoughty Lough, near Kenmare, Co. Kerry. Stream, Bellarena, 

 Co. Derry. Stream near Crossdoney, Co. Cavan. Stream, Killiuey, 

 Stream, Ballybrack, Co. Dublin. 



Navicula acuta, (Wm. Smith). Fresh water. 



Yalve, narrow, lanceolate ; ends acute ; strise costate, convergent 

 in the middle, radiate towards the ends ; length -0046, breadth -0005. 

 (Plate 34, fig. 5.) 



Pinnularia acuta, Wm. Sm., B. D., Yol. i., p. 56, PI. xviii., 

 fig. 171. — ISCavicula radiosa, var. acuta. Grunow, Yerhand. derK. 

 K. Zool. Bot. Gesell., Band x., 1860, p. 526. There is a form described 



