202 Proceedings of the Royal Irish Academy. 
Besides the localities specified by Smith, namely, near Belfast 
and Lough Mourne deposit, I have found the species in the following 
sie :—River Erne, Crossdoney, Co. Cavan; ditch near Wexford ; 
erner’s-bridge, Co. Armagh; Killakee, Co. Dublin; stream near Kil- 
cool, Co. Wicklow; L. Neagh, near the town of Antrim; surface of 
rock near Glenarm, Co. Antrim. 
Orthosira sulcata, (Ehr. Kiitz.) Marine. 
Spines of junction surfaces large, short, and more distant than in 
the former species. Strie on side view linear, radiate, distinct at the 
margin, attenuated towards the centre, which they do not reach; 
punocta at the suture large ; striee on front view linear, direct, parallel 
(Pl. 26, fig. 7.) 
Melosira sulcata, Kiitz. Bac., p. 55, T. i., fig. 57. Ralfs, in 
Pritch., p. 819; Pl. ix., fig. 131; Plate xi., fig. 26. Rab. Fl. Eur. 
p. 41.—Orthosira marina, Wm. Sm., B. D., Vol. u., p. 59; Pl. lin, 
fig. 338.—Gallonella sulcata, Ehr.—Paralia marina, Heiberg, De 
Danske Diat., p. 33. 
Although this species has been described and figured by Kitzing 
as identical with Gallionella sulcata of Ehrenberg, Heiberg attributes 
it to Wm. Smith. The latter indeed has figured it more perfectly 
than Kiitzing has done; still, Kiitzing’s figure, imperfect as it is, 
seems to me unmistakable; and all uncertainty as to the species indi- 
cated is removed by his reference to the Richmond deposit in which 
the form abounds. For this reason I have followed Ralfs and Raben- 
horst in assigning the species to Ehrenberg and Kiitzing, as well as 
restoring the original specific designation. And as J have not been 
able to trace any keel similar in structure and position to that of Lysi- 
gonium, instead of adopting Heiberg’s new genus, Paralia, I leave the 
species where Smith placed it in the present genus. 
Cork and Kinsale Harbours, Wm. Smith. Bannow, River Slaney, 
Killurin, Co. Wexford. Near Wicklow. Malahide. Dalkey, Co. 
Dublin. 
Orthosira Dickiewt, (Thwaites.) Fresh water. 
Cell-cavity sub-spherical. Sutural puncta small and distant. 
Spines on junction surfaces absent. Strie, both on front and side 
view, minutely punctate. Puncta on front view arranged in lines 
parallel to the suture. 
Thwaites, Ann. N. H., 2 series, Vol. i., p. 168, Pl. xii. Wm. Sm., 
B.D., Vol. ii., p. 60, Pl. lii., fig. 3835.—Melosira Dickieii, Kiitz. Sp. Alg., 
p. 889. Ralfs, in Pritch., p. 820, Pl. xv., fig. 29... Rab. Fl. Eur., 
» 43. 
i This species is remarkable for the abnormal growth of frustule 
within frustule, so fully described by Smith, B. D., Vol. ii., PI. lii., 
fig. 335. Thwaites regarded this peculiarity as a mode of developing 
sporangia, while Smith considered it an abnormal development similar 
