O’Mrara—Report on the Irish Diatomacee. 257 
and a portion of the only gathering he ever made of it (near Paris.)”’ 
Q.J.M.S., Oct., 1860, p. 245. Subsequently De Brébisson found the 
same form at Falaise, ‘and gave a figure of it which is confirmatory of 
the opinion of Walker-Arnott. ‘Notes on some French Diatomacee,”’ 
Journal of Queckett Mic. Club for April, 1870, fig. 6. Kiitzing states 
that this species is adnate. I have never seen it so. 
Kiitz. Bac., p. 50, T. xxx., fig. 68. Rab. Siissw. Diat., p. 11. 
Tin jute: 2. Possibly this species may be identical with C. Kiitzin- 
giana, var. B. Wm. Sm., B. D., Vol. i., p. 27; and if so, it is not the 
same that Ralfs has figured as O. rectangula (De Bréb.) Ralfs, in 
Pritch., Pl. v., fig. 54; the latter being antlulate on the front view, 
whereas the present species is rectangular. 
Lucan. Feather-bed mountain, Co.Dublin. Kilcool, Co. Wicklow. 
Cyclotella operculata, (Kiitz.) Fresh water. 
Marginal strie short, fine, linear; central part of valve covered 
with distinct moniliform striez radiately arranged. (Pl. 26, fig. 12.) 
Though Smith, who is followed by Ralfs, describes the striz in 
this species as obscure and very short, the figure in both cases is too 
clear to admit of any doubt as to identification. 
Muti. bad,. p00, a a hes! POT) and. 152) “Wm: Smi;-B.D., 
Vol. 1., Pl. v., fig. 48. Ralfs, im Pritch., p. 811, Pl. v., fig. 53.— 
Orthosira operculata, Heiberg, De Danske Diat., p. 32. Cleve, Om 
Svenska och Norska Diat., p. 217. This form is not identical with 
that described by Walker-Arnott under this name, with the centre 
destitute of strie, but probably is the same as the variety he identifies 
with C. minutula, Kiitz. See Arnott on Cyclotella, Q.J.M.S. for 
Oct., 1860, pp. 246, 247. 
Lower Lake, Killarney, Co. Kerry. Derrylane Lake, Co. Cavan. 
Glenchree, Co. Wicklow. River Bann, near Coleraine, Co. Derry. 
River Erne, Crossdoney, Co. Cavan. Royal Canal, Enfield, Co. Meath. 
Lough Neagh, near Lurgan, Co. Armagh. Lough Mourne deposit. 
Lough Island-Reavy deposit, found also living in the same place. 
Cyclotella operculata, var. Fresh water. 
Margin of valve fringed with short rounded distinct costee, over 
which there is a circle of very fine linear striz, short; centre of the 
valve as in the former, but the moniliform striae much finer and more 
obscure. (Pl. 26, fig. 12, b.) 
On banks of the Liffey, near Ballymore Eustace, Co. Kildare. 
Lough Neagh, near Lurgan, Co. Armagh. 
Cyclotella antiqua, (Wm. Sm.) Fresh water. 
Marginal portion of the valve narrow, marked with short, broad, 
triangularly formed bars, over which there is a circlet of very fine 
short linear strie ; central portion occupied by about nine triangular 
bars which do not reach the centre. (Pl. 26, fig. 13.) 
