O’Mrara—Report on the Irish Diatomacee. 309 
dency towards the elliptical outline, I am disposed to regard these as 
abnormal, the normal character being lnear. Smith indeed distin- 
guishes the two forms by the fact that, in the latter, the frustules 
are loose and scattered, whereas in the former they are arranged 
radiately ; and, although such a feature of growth is not to be wholly 
overlooked, it is scarcely sufficient to distinguish the species, especially 
in the earlier stages of growth, where the frustules are few in number. 
I am inclined to think the form which Smith describes as Synedra 
ulna is really Synedra splendens. It seems strange that this form 
should have been attributed to Wm. Smith, although he regards what 
he calls Synedra radians as equivalent to Synedra splendens, Kiitz. 
Kiutz., Bac., p. 66, T. xiv., fig. 16; Rab. Sussw. Diat., p. 54, 
T. iv., fig. 4? Ralfs,in Pritch., p.788. Grunow, Verhand. der K. K. 
Zool. Bot. Gesel., Band xii., p. 894.—Synedra radians, Wm. Sm., B.D., 
Vol. i, p. 71, Pl. xi., fig. 89. Heiberg, De Danske Diat., p: 64. 
Castracane, Catalogo di Diat. raccolte nell Val Intrasca, p. 10. Cleve, 
Om Svenska och Norska Diat., p. 220. 
Stream, Crossdoney. Derrylane Lough, Co. Cavan. Lucan. 
Friarstown, Bohernabreena, Malahide, Co. Dublin. Tacumshane, Co. 
Wexford. Kailleshin, Queen’s Co. Royal Canal, Enfield, Co. Meath. 
Glencar. Pedlar’s Lough, near Dingle, Co. Kerry. Ditch near railway 
station, Dundalk, Co. Louth. River Suck, Ballinasloe, Co. Galway. 
Var. radians, (Kiitz.) Fresh water. 
Like the typical species, but smaller, and the ends more acute on 
side view. (PI. 28, fig. 30.) 
Kitz. Bac., p. 64, T. xiv., fig.7. Ralfs,in Pritch., p. 787.—Syne- 
wea iaie, Wim po. Bb. Dp. Vol. 1. p..il, Pl xu. fie. 89 B, 
and 89 y. 
Friarstown, Co. Dublin. Derrylane Lough, Co. Cavan. Pedlar’s 
Lough, near Dingle, Co. Kerry. Ditch near Dundalk, Co. Louth. 
Ditches in the Callows, Ballinasloe, Co. Galway. 
Var. danica, (Kiitz.) Fresh water. 
Frustules longer and narrower than the typical species, the stria- 
tion finer, and the valves on front view more gradually attenuated 
towards the ends, which are broadly rounded off, and not capitate. 
(Pl. 28, fig. 31.) 
Kitz. Bac., p. 66, T. xiv., fig. 13.—Ralfs, in Pritch., p. 788; 
Synedra radians var. debilis, Rab. Fl. Eur., sect. 1, p. 1384? Grunow 
considers this var. = Synedra radians, Wm. Sm., B. D., Vol.1., p. 71, 
Pl. xii., figs. 89 B, and 89y; Verhand. der K. K. Zool. Bot., Gesel., 
Band xii., p. 896; but Synedra danica is much longer than that 
variety, less lanceolate, and with broader rounded apices. 
River Moy, near Foxford, C. Mayo. Bantry Well, Farraghy, Co. 
Cork. Donoughmore, Co. Tyrone. Coolnamuck, parish of Dysert, Co. 
Waterford. 
