O'Meara — Rej^ort on the Irish Diatomaeece. 415 



PL xvii., fig. 155, Ralfs, in Pritch., p. 901 ; Cleve, Om Svenska och 

 mrskaDiat., p. 228. Donkin, N. H.Brit. Diat., p. 37, PL v., fig. 14. 

 Scfiumann, Diat. der Hohen Tatra, p. 68. 



Tacumsliane, Co. "Wexford. Bowen's Court, Co. Cork. Lough. 

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

 Co. Waterford. 



Navicula angustata, ("Wm. Smith). Presh water. 

 Valve very narrow, elliptical ; ends produced and slightly capitate. 

 Striae fine, linear, radiate; length -0016, breadth '0003. (Plate 34, 

 fig. 26.) 



"Wm. Sm., B. D., Vol. i., p. 52, PL xvii., fig. 156. Ealfs, in 

 Pritch., p. 901. Castracane, Cataloga di Diat. raccolte nella Yal. In- 

 trasca, p. 12. Schumann, Diat. der Hohen Tatra, p. 68. — IS'avicula 

 crypto cephala, var. rhyncocephala, Grunow, Yerhand. der K. K. Zool. 

 Bot. Gesell., Band x., 1860, p. 527, T. iv., fig. 283. 



Bantry, Co. Cork. Black Castle, Co. Wicklow. Malahide, Co. 

 Dublin. Lough Mask, near Tourmakeady, Co. Mayo. 



Nmicula lagerstedtii, IS", S. Presh water. 



Valve small, rhombic ; ends slightly produced. Striae obviously 

 punctate, radiate, sub-distant; when the centre is not exactly in 

 focus, there is the appearance of a narrow stauroform band, which dis- 

 appears when properly focused; length. '0010, breadth -0005. (Plate 

 34, fig. 27.) 



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

 Kerry. In the latter, marine and fresh water species were mingled, 

 but in the former locality marine influence was impossible ; the form 

 is therefore to be regarded as inhabiting fresh water. 



Navicula gastrum, (Ehr). Presh water. 



Valve rhombic ; ends scarcely produced. Striae linear, convergent 

 in the middle, radiate towards the ends; length •0018, breadth "0009. 

 (Plate 34, fig. 28.) 



Kiitz. Bac, p. 94, T. xxviii., fig. 56, who regards the species as 

 identical with Pinnularia gastrum, Ehrenberg. Ralfs, in Pritch., 

 p. 900. Donkin, N. H. Brit. Diat., p. 22, PI. iii., fig. 10. This figure 

 represents the form as much narrower, and the ends more produced 

 than is the case in my specimens. — Pinnularia gastrum, Bab. Siissw. 

 Diat., p. 44, T. vi., fig. 15. This last figure represents the striae as 

 parallel, which is not accurate. Gregory, Q. J. M. S., 1855, p. 41. 

 Plate iv., fig. 20. 



Dundalk, Co. Louth. Lough Gill, Co. Kerry. Lough Mask, near 

 Tourmakeady, Co. Mayo. Lough Mourne deposit. 



