350 Proceedings of the Royal Irish Academy. 



Namcula Irelissonii, (Kiitz). Fresh "vrater. 



Yalve linear, elliptical; ends somewhat rounded; length '0016, 

 breadth -OOOo ; cost^ fine, radiate ; intermediate free space narroTV, 

 except in the middle, "where it expands, reaching the margin in a 

 staTU'oform band widening towards the margin. (Plate 30, fig. 24.) 



Kiitz. Bac, p. 93, T. iii., fig. 49. Ealfs, in Pritch., p. 897. 

 Gmnow, Yerhand. der K. K. Zool. Bot. Gresell., Band x., 1860, p. 519. 

 — Pinnnlaria stauroneiformis, "Wm. Sm., B.D., Yol. i., p. 57, PL xix., 

 fig. 178. Eab. PI. Eur. Alg., sect, i., p. 222. 



Drumoughty Lough, near Kenmarc, Bantrv, Co. Cork. Deny- 

 lane Lough, Co. Cavan. Ptathdi'um, Peatherbed ITountain, Co. ~^ick- 

 low. Killakee, Co. Dublin. Lough Gill, Co. Keny. 



Navicida brehissonii, rar. anguda, (Grun.) Fresh water. 



Yalve narrow, elliptical ; ends attenuated, and slightly rounded ; 

 length '0016, breadth '00025 ; cost© fine, radiate; intermediate free 

 space naiTow, except in the middle, where it expands, reaching the 

 margin in a staiu'oform band narrower than in the typical species. 

 (Plate 30, fig. 25.) 



Grunow, Yerhand. dur K. K. Zool. Bot. Gesell., Band x., 1860, 

 p. 519, T. v., fig. 18. 



Derrylane Lough, Co. Caran. Camolin, Co. "Wexford. 



Naticula icodauron, (Ehr.) Fresh water. 



Yalve linear, elliptical ; length '0028, breadth 'OOOe ; costoe fine, 

 radiate ; intermediate free space narrow, except in the middle, where 

 it expands into a naiTow stauroform parallel band reaching the marsin. 

 (Plate 30, fig. 27.) 



Stauroptera icostauron, Ehr., as Grunow suggests, Yerhand. der 

 K. K. Zool. Bot. Gesell., Bandx., 1860, p. 519. — Stauroneis icostauron, 

 Kiitz. Bac, p. 106, T. xxix., fis;. 10. — Pinnnlaria viridis, var. B., ^m. 

 Sm., B.D., YoL i., p. 54, PI. xviii., fig. 163 B. 



Lerrylane Lough, Co. Caran. Adrigoole, Co. Kerry. Featherbed 

 Moujitain, Co. Dublin. Lake near Castlewellan, Co. Down. 



Nmicula stauroptera, (Grunow). Fresh water. 



Yalye linear, elKptical, with rounded ends ; length "0025, breadth 

 •0007; eostxe coarse, convergent in the middle, radiate towards the 

 ends ; intermediate fi'ee space narrow, except in the middle, where it is 

 much expanded, appearing sometimes to reach the margin, but really 

 not so. (Plate 30, fig. 28.) 



Grunow, Yerhand. der K. K. Zool. Bot. Gesell., Bandx., 1860, p. 

 516. Stauroptera parva, Ehr., according to Kiitzing. — Stauroneis 

 parva, Kiitz. Bac, p. 106, T. xxix., fig. 23. Gregory has described a 

 form as Pinnnlaria parva, Q. J. ')!. S., 1854, p. 98, PI. iv., fig. 11. To 



