O'Meara — Report on the Irish Diatomacc(?. 311 



(f. ) Strife marginal. 



Synedra talulata, (Agardli.) Marine. 



Frustules large, adhering in tablets on a short stipes; on front vievr' 

 wider at middle than at the ends ; on side vie-w nearly linear, very 

 slightly attenuated towards the constricted and rounded ends ; strise 

 broader than in the succeeding species. (PL 28, fig. 36.) 



Kiitz. 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., 

 Yol. i., p. 72, PL xii., fig. 96. Ealfs, in Pritch., p. 788 ; Gninow, 

 Yerhand. der K. K. Zool. Bot., GeseL, Band xii., 1862, p. 403. Eab. 

 Fl. Eur. Alg., sect. 1, p. 137. Cleve, Om Svenska och i^Torska Diat., 

 220. According to Kiitzing = Diatoma tabulatum, Agardh, on 

 which authority I attribute the species to Agardh, as do also Balfs 

 and Ptabenhorst, while Smith, Cleve, and Grunow, the latter doubt- 

 fully, refer it to Eiitzing. 



On seaweeds, Bannow, Co. "Wexford, as well as on seaweeds near 

 the town of "Wexford. Seaweeds, Eostrevor, Co. Down. Seaweeds, 

 Malahide, Co. Dublin. Laytown, Co. Meath. Breaches near ISTew- 

 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; striae short. (PL 28, fig. 37.) 



Kiitz. Bac, p. 68, T. xxx., fig. 50. Wm. Sm., B. D., Yol. i., p. 

 70, PL xi., fig. 98, PL xii., fig. 98, in which latter the front view and 

 manner of growth are accurately depicted. Ealfs, in Pritch., p. 789, 

 PL iv., fig. 27, where the fi'ont view is represented as straight and 

 perfectly quadrangular, and the side view as arcuate, and with a 

 median line, the striae reaching the latter ; in all these particulars the 

 fig-ure is not correct. Grunow, Yerhand. der K. K. Zool. Bot. GeseL, 

 Band xii., p. 405. Heiberg, De Danske Diat., p. 65. Eab. Tl. Eur., 

 sect. 1, p. 138. 



On seaweeds, Malahide, Monkstown, Bray, Co. Dublin. 



Synedra affinis, (Kiitz.) Marine. 



Frustules in mode of growth similar to the preceding ; on fi'ont 

 view attenuated at ends ; on side view lanceolate ; striae short. (PL 

 28, fig. 38.) 



Kiitz. Bac, p. 68, T. xv., fig. 6. Wm. Sm., B. D., Yol. i., p. 73, 

 PL xii., fig. 97. Ealfs, in Pritch., p. 788. Grunow, Yerhand. der 

 K. K. Zool. Bot. GeseL, Band xii., 1862, p. 403. Eab. EL Eur., 

 sect. 1, p. 138. 



Tide-pool, "Wexford. Tacnmshane, Co. Wexford. On sea-weeds,. 

 Malahide and Clontarf, Co. Dublin. Camlough Bay, Co. Antrim. 



