O’Mrara—Report on the Irish Diatomacee. S11 
(f.) Strie marginal. 
Synedra tabulata, (Agardh.) Marine. 
Frustules large, adhering in tablets on a short stipes; on front view 
wider at middle than at the ends; on side view nearly linear, very 
slightly attenuated towards the constricted and rounded ends; striez 
broader than in the succeeding species. (Pl. 28, fig. 36.) 
Kitz. Bac., p. 68, T. xv., figs. 101-3, where the form is described 
more in accordance with my specimens than that of Wm. Sm., B. D., 
Wolk: ip. (2) Pl. xis. iie 96: Ralis) in Prtch,, p. 788; Grunow, 
Verhand. der K. K. Zool. Bot., Gesel., Band xii., 1862, p. 403. Rab. 
Fl. Eur. Alg., sect. 1, p. 1387. Cleve, Om Svenska och Norska Diat., 
220. According to Kutzing = Diatoma tabulatum, Agardh, on 
which authority I attribute the species to Agardh, as do also Ralfs 
and Rabenhorst, while Smith, Cleve, and Grunow, the latter doubt- 
fully, refer it to Kutzing. 
On seaweeds, Bannow, Co. Wexford, as well as on seaweeds near 
the town of Wexford. Seaweeds, Rostrevor, Co. Down. Seaweeds, 
Malahide, Co. Dublin. Laytown, Co. Meath. Breaches near New- 
castle, Co. Dublin. Seaweeds, Larne, Co. Antrim. 
Synedra arcus, (Kiitz.) Marine. 
Frustules much smaller than those of the preceding species, and 
not dissimilar in their mode of growth; on front view slightly arcu- 
ate; on side view slightly sigmoid; strie short. (PI. 28, fig. 37.) 
Knitze, Bac. p. 68) TE. maxx wie 50. 5 Wan.-Sms,<BD.,oVolni.3) p. 
70, Pl. xi., fig. 98, Pl. xi., fig. 98, im which latter the front view and 
manner of growth are accurately depicted. Ralfs, in Pritch., p. 789, 
Pl. iv., fig. 27, where the front view is represented as straight and 
perfectly quadrangular, and the side view as arcuate, and with a 
median line, the striz reaching the latter; in all these particulars the 
figure is not correct. Grunow, Verhand. der K. K. Zool. Bot. Gesel., 
Band xii., p. 405. Heiberg, De Danske Diat., p.65. Rab. FI. Eur., 
sect. 1, p. Les. 
On seaweeds, Malahide, Monkstown, Bray, Co. Dublin. 
Synedra affinis, (Kiitz.) Marine. 
Frustules in mode of growth similar to the preceding; on front 
_ view attenuated at ends; on side view lanceolate; strie short. (PI. 
28, fig. 38.) 
Kanevbae.,. po6s,) L) xy, .ne-6.)"-Wm. Sm.; B.D; Vol. 1.; 'p. 73, 
Pl. xii., fig. 97. Ralfs, in Pritch., p. 788. Grunow, Verhand. der 
K. K. Zool. Bot. Gesel., Band xu., 1862, p. 403. Rab. Fl. Eur., 
sect. I, p. 138. 
Tide-pool, Wexford. Tacumshane, Co. Wexford. On sca-weeds, 
Malahide and Clontarf, Co. Dublin. Camlough Bay, Co. Antrim. 
