O'Meara — B,epovt on the Irish Diatomacea\ 319 



identical -vritli Diatoma arcuatum, Lyngbye. "Wm. Sm. B. D., Vol. ii., 

 p. 34, PI. xxxviii., fig. 305. Ralfs, in Pritch., p. 804. Gninow, 

 Verhaud. der K. K. Zool. Bot. Gesel., Band xii., p. 423. Heiberg, Dc 

 Danske Diat., p. 70. Rab. PL Eur., sect. 1, p. 306. Clere, Oin 

 Svenska och Xorska Diat., p. 221. 



Salt ditch, near "Wexford. Taciimshanc, Co. Wexford. Malabide, 

 Ballybrack, Co. DubHa. Camlough. Bay. Sea-weeds, Portrusli, 

 Co. Antrim. Sea-weeds, Dundalk, Co. Loiith. Sea-weeds near 

 Oalway town. Arran Islands, Co. Galway. 



RhaMonema minutum, (Kiitz.) Marine. 



Valves small ; expanded in the middle ; attenuated towards tlic 

 rounded ends ; striae moniliform, pervious ; diaphragms few ; appa- 

 rently alternate, with a single foramen. 



Kutz. Bac, p. 126, T. xxi., fig. 2, 4. Wm. Sm., B. D., Yol. ii., 

 p. 35, PI. xxxviii., fig. 306. Ealfs, in Pritch., p. 804, PL iv., fig. 41. 

 Grunow, Yerhand. der K. K. Zool. Bot. Gesel., Band xii., 1862, p. 423, 

 Heiberg, De Danske Diat., p. 70. Eab. PL Eiu\, sect. 1, p. 306. 

 Cleve, Om Svenska och Xorska Diat., p. 221. 



Sea-weeds, Malahide ; on piles of wooden bridge, DoUymount 

 Strand, Ballybrack, Salt Hill, Co. Dublin. Sea-weeds, Portrush. 

 Lame, Co. Antiim. Tacumshane, Co. "Wexford. Dimdalk, Co. Louth. 



KhaMonema adriaticivn, (Kiitz.) ITarine. 



PiT-istules very large ; valves narrow, linear elliptical ; striaj 

 moniliform ; diaphragms numerous, not so wide on margins nor so 

 strongly costate as on E. arcuatum, with two or more foramina. 



Kiitz. Bac, p. 126, T. xviii., fig. 7. Wm. Sm., B. D., Yol. ii., 

 p. 35, PL xxxviii., fig. 305 a, b. Ralfs, in Pritch., p. 805, PL xiii., 

 fig. 27. Grunow, Yerhand. der K. K. Zool. Bot. Gesel., Band xii., 

 1862, p. 424. Rab. PL Em-., sect. 1, p. 306. Cleve, Om Svenska 

 och Xorska Diat., p. 221. 



lEalahido, Co. Dublin. '' Cork Harbour. Belfast Bay, near Car- 

 rickfergus." Wm. Smith. 



Genus Y. Sxeiatella, Agardh. 



FrustiLles stipitate ; stipes long ; valves elliptical, lanceolate, with 

 ti median line, without central or terminal nodule ; striae obsolete ; 

 diaphragms numerous, on front view linear, unstriate, strongly 

 marked at one end, and gradually attenuated towards the other ; not 

 reaching the entire breadth of the valves ; arranged alternately ; on 

 eide view not reaching the full length of valve ; open the greater part 

 of the length. 



