I 



O'Meara — RejMvt on the Irish DiatomacecB. 259 



There is a form resembling the present, described by Ehrenberg as 

 Discoplea atmospherica, from l^epal, Mic, T. xxxii. v., fig. 4 ; and 

 also from Fayoom, Egypt, Mic, T. xxxii. i., fig. 3; biit as the figures 

 of Discoplea atmospherica differ so widely from one another, even if 

 there were no doubt as to the identity, a different name is needful to 

 mark the peculiarity of the present species. 



Lough IPTeagh, near Lurgan, Co. Armagh. Lough Mask, near 

 Tourmakeady, Co. Mayo. There is a form occurring in the Lough 

 Mourne deposit, which may be the same as this, but the papillae are 

 usually injured, and, judging from the traces that remain, they seem 

 to have been more numerous, more slender, and more scattered than in 

 the living forms. 



Cyclotella Scotica, (Kiitz.) Marine. 



Yalve very small, finely striate on the margin; the centre unstriate. 

 Kiitz. 



Bac, p. 50, T. i., figs. 2 and 3. Ralfs, in Pritch,, p. 811. PI. 

 xiv., fig. 17. (PI. 26, fig. 16.) 



On sea- weeds at the Griants' Causeway, Co. Antrim. Kiitzing and 

 Ralfs describe this species as adnate, but as my specimens had been 

 treated with acid before observation, I cannot confirm this character. 



Cyclotella dallasiana, (W. Sm.) Marine. 



Margin of the valve coarsely striate ; central part rugose, as if blis- 

 tered. Smith represents the central part as " cellulate ;" butWalker- 

 Arnott has more accurately described it as ''puckered, or as if blis- 

 tered." 



Wm.'Sm., B. D., Vol. ii., p. 87. Walker-Arnott, Q. J. M. S, Oct., 

 1860, p. 245. Ealfs, in Pritch., p. 813. Rab. El. Eur., p. 33. 



Stomachs of Ascidians. Roundstone Bay, Co. Galway. 



Cyclotella punctata, ("Wm. Sm.) Freshwater. 



Frustules undulate on front view ; on side view, striae close, radiate, 

 very finely punctate, puncta smaller towards the margin, which latter 

 is surrounded by a circlet of short, fine costse. (PI. 26, fig. 17.) 



Wm. Sm., B. D., Yol. ii., p. 87. RaKs, in Pritch., p. 813. PI. viii., 

 fig. 13. Rab. El. Eur., p. 33. 



Lough Island-Reavey, Co. Down, Eloat bog, Co. Westmeath. 



Genus YI. Coscinodisctjs, Ehr. 



Erustules simple, free, lenticular; valve generally uniformly striate. 

 -Strife areolate or moniliform. "Without processes or undulations. 



Kutzing noticed the close affinity between Melosira and the pre- 

 sent genus, but in his classification placed them very widely apart, 



