262 Proceedings of the Royal Irish Academy. 
Coscinodiscus radiatus, (Ehr.) Marine. 
Cellules large, hexagonal, radiate, somewhat smaller near the 
margin. 
Bbr Mie. PB. ex,,o fig: 1. Katz. Bac, ie. ae, Pi: he. 08. 
Wm. Sm., B.D. Vol, i:,+p. 28, Pl. it., fig Bi belies im Praehe: 
p- 830, Pl. x1., figs. 39 and 40. Heiberg, De Danske Diat., p. 36. 
Cleve, Om Svenska och Norska Diat., p. 218. Rab. Fl. Eur., p. 34. 
On sea-weeds, Bannow, County Wexford. Piles of wooden bridge, 
Dollymount; Malahide. Stomach of Pectens, Dalkey. On corallines, 
Howth. On sea weeds, Ballybrack, County Dublin. On sea weeds, 
Kilkee, County Clare. From stomachs of Ascidians, coast of County 
Clare. 
Coscinodiscus radiolatus, (Khr.) Marine. 
Disk small, cellules minute, obscurely hexagonal, arranged partly 
in radiate bands, and partly in the intervals of these bands in converg- 
ing lines. Cellules confused at the centre of the disk, smaller towards 
the margin. (Pl. 26, fig. 22.) 
Kiitz. Bac., p. 132, T. xxix., fig. 91. Ralfs, in Pritch., p. 830, who 
describes the form thus :—‘‘ Cellules punctiform, equal, radiating,” 
whereas, in fact, they are minutely hexagonal, and diminish slightly 
near the margin. 
Oyster shells, Dublin Bay. Tide-pool,? Dalkey, County Dublin. 
Stomachs of Ascidians, Roundstone Bay, County Galway. Stomachs of 
Ascidians, County Clare. 
Coscinodiscus cervinus, (Brightwell.) Marine. 
Cellules very minute, radiate, close, dry valve fawn-coloured, frus- 
tule convex. 
Brightwell has described and figured this form as Hyalodiscus cer- 
vinus, Q.J.M.S., Vol. viii., p. 95, Pl. vi., fig..13.. He deseribes the 
‘‘puncta or dots’? as ‘‘ scattered over the whole surface ;” butin his 
figure represents them as regularly radiate, which latter corresponds 
exactly with my specimens. Ralfs, in Pritch., p. 831, places the form 
among the doubtful species of Coscinodiscus, to which genus it pro- 
perly belongs. 
From stomachs of Ascidians, Roundstone Bay, County Galway. 
From stomachs of Ascidians, County Clare. 
Coscinodiscus Smith, (Wm. Sm.) Fresh water. 
Disk small, punctate, puncta regularly radiate. 
Wm. &Sm., B. D., Vol.-1., p. 23, Pl. in., fig. 36. 
Smith has unaccountably confounded this form with Coscinodiscus 
minor, Ehr., from which it is plainly distinguished, both by its habitat 
and the character of the striation ; the latter being marine and areolate, 
the former a fresh water species, and punctate. 
