380 Proceedings of the Royal Irish Academy. 



Navicula didliensis, (Gregory). Marine. 



Yalve broadly elliptical, with, rounded ends ; "intermediate free 

 space narrow, linear, but slightly expanded at the central nodule ; 

 striae moniliform ; puncta small, close, nearly parallel in the middle, 

 and divergently radiate towards the ends; length, -0020; breadth, 

 •0013. (Plate 32, fig. 9.) 



Gregory, Diat. of Clyde, p. 478, PL ix., fig. 2, Ralfs, in Pritch., 

 p. 909, PI. vii., fig. 73. Rab. Fl. Eur. Alg., p. 184.— ^""avicula 

 erythraea, Grunow, Yerhand. der K. K. Zool, Bot. Geseil., Band x., 

 1860, p. 539, T. v., fig. 17. 



Ptiver Slaney, near Killurin, Co. Wexford. Stomachs of Ascidians, 

 Roundstone Bay, Co. Gahvay. 



Var. producta, {O'liieaxa.). Marine. 



Precisely as the typical species, but having the ends slightly pro- 

 duced ; length -0025, 'breadth -0011. (Plate 32, fig. 9a.) 



Stomachs of Ascidians, Broadhaven Bay, Co. Galway. 



Navicida pxmctata, (Kiitz.) Fresh water. 



Yalve elliptical, ends produced, narrow, capitate ; intermediate 

 free space narrow, except in middle, where it expands into a 

 tolerably broad staurof orm band, widening towards the outer end ; 

 striije moniliform; puncta small; radiate; length •0032, breadth. 

 •0010. (Plate 32, fig. 10.) 



Donldn, IST. H. Brit. Diat., p. 36, PL v., fig. 12. Lagerstedt, 

 Sotvat. Diat. fran Spetsberger och Beeren Eiland, p. 29. — Stauroneis 

 punctata, Kiitz., Bac, p. 100, T. xxi., fig. 9. Wm. Sm., B. D., 

 Vol. i., p. 61, PL xix., fig. 189. Ealfs, in Pritch., p. 912. Grunow, 

 Verhand. der K. K. Zool. Bot. GeselL, Band x., 1860, p. 565. Castra- 

 cane, Catalogo di Diat. raccolte nella Val Intrasca, p. 11. Cleve, 

 Om Svenska och ISTorska Diat., p. 228. Eab. PL Eur., Alg., sect. 

 i., p. 245. — Stauroptera punctata, Bab. Siissw. Diat., p. 50, T. ix., 

 fig. 11. 



Biver Slaney, near Xillurin, Co. Wexford. Drumoughty Lough, 

 near Kenmare, Lower Lake, Killarncy, Lough Gill, Co. Kerry. 

 Lough Mask, near Tourmakeady, Co. Mayo. Lough Mourne deposit, 

 Co. Antrim. 



Navicula lacustris, (Gregory). Fresh water. 



Similar to Navicula punctata, but the striae are very much finer ; 

 and the intermediate free space expanded roundly, instead of in a 

 stauroform band ; length about -0020, breadth -0006. (Plate 32, fig. 11.) 



Gregory, (Q. J". M. S., 1856, p. 6, PL L, fig. 23.) describes 

 two distinct varieties, one elliptical, the other with linear margin 

 and produced ends. He also refers to an intermediate form, which- 



