416 Proceedings of the Royal Irish Academy. 
Navicula binodis, (Ehr). Fresh water. 
Valve small, narrow, incurved; ends produced, apiculate. Striz fine, 
linear, radiate; length 0012, breadth -0004; breadth in the middle 
‘00035. (Plate 34, fig. 29.) 
Kiitzing (Bac., p. 100, T. i., fig. 35,) considers the form iden- 
tical with that so named by Ehrenberg. Wm. Sm., B.D., Vol. 1., 
p. 538, Pl. xvu., fig. 159. Rab. Siissw. Diat., p. 41, T'. v., fig. 5, and 
Fl. Eur. Alg., sect. 1., p. 203. Ralfs, in Pritch., p. 893. Castracane, 
Catalogo di Diat. raccolte nella Val. Intrasca, p. 12. Heiberg, De 
Danske Diat., p. 88. Cleve, Om Svenska och Norska Diat., p. 227. 
Donkin, N. H. Brit. Diat., p. 38, Pl. vi., fig. 3. Schumann, Diat. der 
Hohen Tatra, p. 77. 
Powerscourt, Co. Wicklow. Lough Gill, Co. Kerry. Donkin 
considers this species as one which occurs frequently in England; it 
is, however, one of very rare occurrence in Ireland. 
Navicula dicephala, (Ehr.) Fresh water. 
Valve small, narrow, linear, narrowing towards the produced 
slightly capitate ends. Striz obvious, convergent in the middle, radiate 
towards the ends; length :0014, breadth :00055. (Plate 34, fig. 30.) 
Kiitz. Bac., p. 96, T. xxvii., figs. 60 and 62; these figures incor- 
rectly describe the striz as parallel. Kiitzing attributes the species 
to Ehrenberg. Wm. Sm., B.D., Vol. i., p. 53, Pl. xvu., fig. 157. 
Grunow, Verhand. der K.K. Zool. Bot. Gesell., Band x,, p. 538, T. iv., 
fig. 45. Ralfs, in Pritch., p. 902. 
Lough Gill, Co. Kerry. Lough Neagh, near Lurgan, Co. Armagh. 
Camolin, Co. Wexford. Friarstown, Lucan, Killakee, River Dodder, 
Co. Dublin. Cushendun, Co. Antrim. Powerscourt, Co. Wicklow. 
Lough Mourne deposit. : 
Navicula rhyncocephala, (Kiitz.) Fresh water. 
Valve narrow, elliptical; ends considerably produced, not capitate. 
Striz distinct, closely moniliform, radiate; length -0025, breadth 
0006. (Plate 34, fig. 31.) 
Kitz. -Bac-, 2p. 152, TP. xxx. die. (35.. Wins Smee Bo) Vobra.. 
p. 47, Pl. xvi., fig. 1382. Grunow, Verhand. der K. K. Zool. Bot. 
Gesell., Band x., 1860, p. 530, T. iv., fig. 32. Heiberg, De Danske 
Diat., p. 82. Ralfs, in Pritch., p. 900, Pl. vu., fig. 68. Cleve, Om 
Svenska och Norska Diat., p. 227. Schumann, Diat. der Hohen Tatra, 
p. 68. ‘Rab, Fl. Kur. Alg., sect. i., p. 196. ) Donkin, N. H. Brit. 
Diat., p.°38, PE vi, fig. 4. 
River Dodder, ditch, Dundrum, Co. Dublin. Caumlough, near 
Tralee, Co. Kerry. Ulster Canal, near Poyntzpass, Co. Armagh. 
Kilcool, Co. Wicklow. 
