336 Proceedings of the Royal Irish Academy, 



anotlicr in all respects that, judging from the frusttiles alone, I ant 

 disposed to consider that it is not distinct from the present ; nor does, 

 the general appearance of the fronds differ so much as to be irrecon- 

 cilable with this impression. 



Harvey's Manual, p. 210. Wm. Sm., B. D., Vol ii., p. 79, PL lix., 

 fig. 370. Eab. Fl. Eur., sect, i., p. 273. — Schizonema scoparium, 

 Kiitz. Bac, p. 114, T. xxvii., fig. 1. — Micromega laciniatum, E,aKs,. 

 in Pritch., p. 932. 



Carrickfergus to Antrim, collected by Dr. David Moore. Galway,. 

 collected by M'Calla. 



Schizonema yracilli mum, (Wm. Sm.) Marine. 



" Prond capillary, simple below ; sparingly branched and sub-mem- 

 branous towards the apices. Prustules crowded in irregular files. 

 Valves elliptico-lanceolate. Length of frustule .0009, breadth of valve- 

 •00015." — Wm. Smith. Striae linear, very slightly radiate. Prustule on 

 front view narrow, quadrangular. So far as the frustules are concerned, 

 in outline and general appearacce the species differs little from Schi- 

 zonema parasiticum. The stria3 may be a little coarser and the valve 

 somewhat narrower. 



Wm. Smith, B. D., Vol. ii., p. 79, PI. lix., fig. 372.— Micromega 

 gracillimum, Ealfs, in Pritch., j)- 934. 



ITanny water. Lay town, Co. Meath. 



(Iff). Frushdes tcithout strice. 



Schizonema ohtusum, (Grev.) Marino. 



" Frond filiform, si^aringly branched, apices abrupt. Frustules^ 

 exceedingly numerous, in irregular files ; valves elliptical. Length of 

 frond I"; length of frustule -0011; breadth of valve -00025." Wm. 

 Smith. To which should be added that the valves are rounded at the- 

 ends. (PI. 29, fig. 20.) 



Greville, Brit. Fl., p. 413. Harvey's Manual, p. 209. Eab. Fl. 

 Eur., sect. 1, p. 272. — Micromega obtusum, Ealfs, in Pritch., p. 931. 



J^ear Dunkice Castle, Portballintrae, Co. Antrim, collected by 

 Dr. David Moore. Merrion, Malahide, Co. Dublin. Galway. 



Schizonema dilwynii, (Agardh.) Marine. 



"Frond capillary throughout, sparingly branched, tenacious; apices 

 acute. Frustides exceedingly crowded towards the apices, scattered and 

 remote in the older portions. Valves lanceolate, acute. Length of frond 

 2" to 5", or upwards ; length of frustule -0008 ; breadth of valve -0002." 

 AVm. Smith. So far as the frustules are concerned there is but little 

 difference between this and the preceding species ; the only difference- 



