O’Mrara—Report on the Irish Diatomacee. 319 
identical with Diatoma arcuatum, Lyngbye. Wm. Sm. B.D., Vol. u., 
p. 34, Pl. xxxviii., fig. 305. Ralfs, in Pritch., p. 804. Grunow, 
Verhand. der K. K. Zool. Bot. Gesel., Band xii., p. 423. Heiberg, De 
Danske Diat., p. 70. Rab. Fl. Eur., sect. 1, p. 306. Cleve, Om 
Svenska och Norska Diat., p. 221. 
Salt ditch, near Wexford. Tacumshane, Co. Wexford. Malahide, 
Ballybrack, Co. Dublin. Carnlough Bay. Sea-weeds, Portrush, 
Co. Antrim. Sea-weeds, Dundalk, Co. Louth. Sea-weeds near 
Galway town. Arran Islands, Co. Galway. 
Rhabdonema minutum, (Kutz.) Marine. 
Valves small; expanded in the middle; attenuated towards the 
rounded ends; strie moniliform, pervious; diaphragms few; appa- 
rently alternate, with a single foramen. 
Kutz Rael p. 926) el > xxis, fig.42,°49 Wm. Sm.; B.D.) Vol. 1.; 
p. 35, Pl. xxxviii., fig. 306. Ralfs, in Pritch., p. 804, Pl.iv., fig. 41. 
Grunow, Verhand. der K. K. Zool. Bot. Gesel., Band xu., 1862, p. 423. 
Heiberg, De Danske Diat., p. 70. Rab. Fl. Eur., sect. 1, p. 306. 
Cleve, Om Svenska och Norska Diat., p. 221. 
Sea-weeds, Malahide; on piles of wooden bridge, Dollymount 
Strand, Ballybrack, Salt Hill, Co. Dublin. Sea-weeds, Portrush. 
Larne, Co. Antrim. Tacumshane, Co. Wexford. Dundalk, Co. Louth. 
Rhabdonema adriaticum, (Kiitz.) Marine. 
Frustules very large; valves narrow, linear elliptical; strix 
moniliform ; diaphragms numerous, not so wide on margins nor so 
strongly costate as on R. arcuatum, with two or more foramina. 
Kutz. ;Baes ps,.126, (Cy xvur., fie. 7. Wm. sm., B.D, Vol:.u., 
Prod, Elixxxwu. fie. 300 a;-b:;’-Ralis, m -Prtch.,, p: 80, PI. xii1., 
fig. 27. Grunow, Verhand. der K. K. Zool. Bot. Gesel., Band xi.., 
1862, p. 424. Rab. Fl. Eur., sect. 1, p. 306. Cleve, Om Svenska 
och Norska Diat., p. 221. 
Malahide, Co. Dublin. ‘‘ Cork Harbour. Belfast Bay, near Car- 
rickfergus.”?’ Wm. Smith. 
Genus V. Srrraterta, Agardh. 
Frustules stipitate ; stipes long; valves elliptical, lanceolate, with 
a median line, without central or terminal nodule; strie 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 
side view not reaching the full length of valve; open the greater part 
of the length. 
