O'Meara — Report on the Irish Diatomacece. 353 



NavicuJa licapitata, var. crucifera. Presh. water. 



Yalve linear in the middle, attenuated towards the capitate ends. 

 Lengtli -0024 ; breadth. '0006. Costse fine, radiate ; intermediate free 

 space naiTOTT, except in the middle, where it expands into a nan'ow 

 stauroform band, reaching to the margin, and wider there than at the 

 centre. (PI. 30, fig. 33.) 



Pinnularia interrupta, "^^m. Sm., B. D., Yol. i., p. 59, PI. xis., 

 fig. 184. "Were it not for the figure of Smith, just referred to, it 

 would be difiicult to identify this form. Smith alleges that it is iden- 

 tical with Stauroneis parya, Kiitz. Bac, p. 106, T. ssix., fig. 23 ; but 

 that form, as described by Kiitzing, is elliptical, and has not capitate 

 ends, in consequence of which I consider the species quite distinct. 

 The specific name adopted by Smith was pre^dously appropriated by 

 Kiitzing for a form belonging to the genus JSTavicula, which that 

 form still retains ; for which reason I have changed the specific desig- 

 nation. — jSTavicula parya, Ralfs, inPritch., p. 897. This description is 

 giyen obyiously on the supposition that Pinnularia interrupta, (Wm. 

 Sm.,) was identical with Stauroneis parya, Kiitz. But a comparison 

 of the figures renders the accui'acy of this supposition more than 

 doubtful. 



Pool near Glengarrin, Co. Cork. Lough Gill, Co. Kerry. Eiyer 

 at Port-na-Crush, Co. Donegal. Ditch, Cushendun, Co. Antrim. 

 Gayagh, Co. Derry. Pool near Glenchree, Co. Wicklow. 



Navicxda licapitata, var. constricta, (Grunow). Fresh water. 



Yalyes slightly incuryed in the middle ; ends much produced, nar- 

 rowed, and but slightly capitate. Length -0025, breadth in middle 

 •0006. Costse fine, radiate. Intermediate free space narrow, except 

 in the middle, where it expands to the margin in a narrow stauroform 

 band, widening at margin. (PL 30, fig. 34.) 



iN'ayicula mesolepta, yar. constricta, Gnmow, Yerhand. der K. K. 

 Zool. Bot. GeselL, Band x., 1860, p. 521, T. iy., fig. 22, C. Inas- 

 much as the typical form of N'ayicula mesolepta has persistent costse, 

 whereas in the present case the costae are obyiously interrupted in the 

 middle, I prefer to regard this form as ayariety of ISTayicula bicapitata. 



Featherbed Bog, Co. Dublin. Camolin, Co. Wexford. 



Navicula termes, (Ehr.) Fresh water. 



Yalye narrow, oblong. Length -0035, breadth -0006 ; slightly 

 incuryed in the middle ; ends much produced, slightly constricted. 

 Costae short, slightly radiate ; intermecUate free space wide, sometimes 

 reaching the margin in a stauroform band. (PL 30, fig. 35.) 



Kayicula termes, var. nodulosa, Kiitz. Bac, p. 101, T. xxyiii., fig. 71, 

 in which the costae are represented as reaching the median line, 

 whereas in the present form they are marginal. Kiitzing regards the 



