204 Proceedings of the Royal Irish Academy. 
deviates so much from the normal appearance of the species, that one 
may almost take it for certain that it represents a very different form, 
for a difference of so much importance could scarcely have arisen from 
inadvertence.”—De Danske Diat., p. 31. In Thwaites’ original 
* description of Aulocoseira crenulata, Kiitz. = Melosira orichalcea, Ralfs 
(and Orthosira orichaleea, Wm. Sm.), both the generic definition and 
the figure are inapplicable to the present species as figured by Smith. 
‘Aulacoseira cellulis cylindricis, d¢sulcatis, extremitatibus plus minusve 
rotundatis, in filamenta concatenatis.”?’ Ann. of Nat. Hist. March, 
1848, p. 7, most correctly describes Orthosira Roeseana, Rab. = O. 
spinosa (Wm. Sm.). The frustules, as described ib. Pl. xi., B., figs. 
1, 2, and 8, are greatly more like that form than any other species, 
and the side view, as represented in the sporangial frustule, is pre- 
cisely as the side view of that species is described by Smith, B. D., 
Vol. i1., p. 62, Pl. 1xi., fig. 386. I am therefore disposed to think 
that it was not Orthosira orichalcea, but Orthosira Roeseana, which 
Thwaites observed in the process of forming sporangia, or, as Pfitzer 
designates them, Auxospores. 
Smith’s Trish localities are—Well at Seven Churches; Clonmac- 
noise; Moanarone, County Cork; Lough Mourne deposit; to which I 
have to add the following :—River Erne, Crossdoney, County Cayan ; 
Lough Islandreavyy, County Down; Lough Neagh, near the town of 
Lurgan, County Armagh; Killakee and Glenchree, County Dublin. 
Orthosira punctata, (Wm.Sm.) Fresh water. 
This species is distinguished from the preceding chiefly by the fact 
that in this the puncta are very much larger, and more regularly 
arranged; they are parallel to the suture, and so regularly placed that 
they sometimes appear to run spirally. Heiberg remarks that ‘‘ Smith’s 
species is easily recognised by the obvious rows of puncta crossing one 
another, which run in oblique spirals from the suture up to and over 
the side view.’”’—De Danske Diat. p. 831. These last words seem to 
imply that the side view is punctate like the front view; if so, then 
the species must be regarded as certainly distinct from the preceding. 
Smith does not figure the side view, and, in consequence of the length 
of the frustule, it is difficult to turn it over so as to get it under 
observation. In one case only could I get a view of it, and then only 
obliquely ; in this aspect it appeared strongly punctate. The circle of 
spines at the suture is absent in this species as in the last. 
Ralfs, in Pritchard, p. 820, makes this species synonymous with 
Melosira granulata = Gallionella granulata, Ehr. and Rabenhorst, Fl. 
Eur., p. 43, adopts the same course; but so much uncertainty charac- 
terises Ehrenberg’s figures of that species, I prefer, with Heiberg, to 
adopt the precise figure of Smith, and attribute the species to him. 
Ulster Canal, near Poyntzpass. Lough Neagh, near Lurgan, County 
Armagh. 
