382 Proceedings of the Royftl Irish Academy. 



Lough Gill, Co. Kerry, River Bann, near Coleraine ; Bellarena, Co, 

 Derry. Brackish, ditches near town of Gal way. Portmarnock, Co. 

 Dublin. 



Var. lanceolata, (Griinow). Marine or brackish water. 



Yalve lanceolate, ends produced ; relatively longer and narrower 

 than the typical species. Length "0024, breadth -0008. 



Xavicula tumida, var. lanceolata, Grunow, Yerhand. der K. K. 

 Zool. Bot. Gesell., Band x., 1860, p. 537, T. iv. fig. 44. This as well 

 as the preceding species, being both incidental to marine or brackish 

 water, can scarcely be regarded as varieties of ISTavicula tumida, which 

 is a fresh water species. 



Portmarnock, Co. Dublin. Breaches near Newcastle, Co. "Wicklow. 



Nmicida tumida, (Wm. Sm.) Presh water. 



Valve small, elliptical, Avith short capitate ends ; intermediate free 

 space narrow, slightly expanded in the middle ; stri^ close, monili- 

 form ; convergent in the middle, and radiate towards the ends ; 

 length varying fi'om -0013 to -0020 ; breadth fi'om -0005 to -0008. 



Wm. Sm., B. D., Yol. i., p. 53, PL xvii., fig. 146. Grunow, 

 Verhand. der K. K. Zool. Bot. Gesell., Band x., 1860, p. 537, T. iv., 

 fig. Aoa. Cleve, Om Svenska och Norska Diat., p. 226. — JSTavicula 

 Angiica, Ealfs, in Pritch., p. 900. Rab. Fl. Eui'. Alg., sect, i., 

 p. 193. Donkin, Is^. H. Brit. Diat., p. 35, PI. v., fig. 11^. 



Kilcool ; streamlet in Powerscourt demesne, Co. "Wicklow. Lough 

 Mask, Tourmakeady, Co. Mayo. Ditch near town of Sligo. 



Var. linearis, (O'Meara). Presh water. 



Similar to the typical form, but sides linear, ends slightly jDro- 

 duced; striae coarser, obviously moniliform, radiate; length -0011, 

 breadth -0005. (Plate 32, fig. 15.) 



Lough Gill, Co. Kerry. Lough Mask, Tourmakeady, Co. Mayo. 



Navicula pulchra, (Gregory). Marine. 



Yalve lanceolate ; intermediate free space narrow, expanded in the 

 middle; strige distinctly moniliform, radiate; length "0027, breadth 

 •0008. (Plate 32, fig. \Q.) 



Gregory, Q. J. M. S., 1856, Trans., p. 42, PI. v., fig. 7. EaKs, in 

 Pritch., p. 906. Eab. PI. Eur. Alg., sect, i., p. 176. 



Galway Bay near the town of Galway. 



