O'Meara — Eeport on the Irish Diatomacece. 305 



Var. linearis, (TTm. Sm.) Presh. water. 



Smaller than the preceding yar., and on side "new somewhat 

 liaear. (PL 28, fig. 21.) 



Synedi'a fascicnlata, "Wm. Sm., B.D., Yol. i., p. 73, PI. xi., fig. 

 100, who has inacciu'ately confounded this fresh water species with 

 Synedra fascicnlata, Kiitz. Bac, p. 68, T. sv., fig. 5, which is clearly 

 a marine species. — Synedra parrula, Kiitz., according to Grunow, 

 Verhand. der Zool. Bot. Gesel., Band xii., 1862, p. 392, T. iv., fig. 17, 

 where the form is accurately figured ; hut as it is impossible to identify 

 it with Kiitzing's figure of the species so named, I consider it more 

 conducive to accuracy to refer this species to Smith, who has so accu- 

 rately described it ; and as his specific name must be abandoned for the 

 reason given, and that adopted by Grunow is not quite certain, I have 

 given it a name characteristic of its general appearance. It is to be 

 noted that Smith separates this form from those with which it stands 

 related ; but Grunow and Babenhorst coincide with me as to its inti- 

 mate relation to the group of which Synedra pulchella is the type. 



Tacumshane, Co. ^^exford. Tide pool, ITalahide. In both which 

 marine and fi'esh water forms were mixed up, but I found it likewise 

 mixed with the preceding variety on the surface of wet rocks at 

 Black Castle, Co. Wicklow. 



(d.) StricB interrupted hy a narrow longitudinal sulcus; valves 

 linear. 



Synedra capitata, (Ehr.) Fresh water. 



Prustule on front view linear, expanded slightly at the ends ; on 

 side view linear, with expanded triangular head. (PI. 28, fig. 22.) 



Ehr. Infus. T. xxi., fig. 29. Kiitz. Bac, p. 67, T. xiv., fig. 19. 

 Wm. Sm.. B.D., Yol. i., p. 72, PI. xii., fig. 94. Eab. Siissw. Diat., 

 p. 55, T. iv., fig. 6. Ealfs, in Pritch., p. 788, PL iv., fig. 29, and x., 

 fig. 185. Grunow, Yerhand. der K. K. Zool. Bot. Gesel., Band xii., 

 1862, p-. 394. Heiberg, De Danske Diat. p. &b. Cleve, Om Svenska 

 och jN'orska Diat., p. 220. 



In Smith's figure there appears a short median line terminating 

 towards the centre in small pear-shaped nodules, and also a central 

 free space ; the same features appear in the figiire of Ealfs, in Pritchard, 

 but these peculiarities do not occur in the numerous specimens which 

 have come under my observation. 



Tacumshane, Co. Wexford. Ditch at railway station, Dundalk, 

 Co. Louth. Stream, Crossdoney, Co. Cavan. Lucan. Dundrum. 

 Boat harbour. Dolphin's bam, Co. Dublin. Eoyal Canal, Enfield, Co. 

 Meath. Eoyal Canal, Kilcock, Co. Kildare. Kilcool, Co. Wicklow. 

 The Callows, Ballinasloe, Co. Galway. Limestone quarry, MuUingar, 

 Co. Y\"estmeath. Lough Moume deposit. 



