O’Mrara—Report on the Irish Diatomacee. 277 
all cases substantiated by observation, but because it seems the most 
satisfactory. And not being in a position either to sustain or refute 
the assumption, I consider the proper course is to leave them as they 
stand. 
Genus I. Ampuirerras, Ehr. 
Frustules concatenate ; cubical; processes springing from each angle 
of the valve short. 
Amphitetras antediluviana, (Ehr.) Marine. 
Striation areolate ; connecting zone more finely areolate than the 
valve. On side view, margins deeply concave ; areoles radiate and con- 
centric. (PI. 27, fig. 10.) 
Kone: “Bae: ip: Poo, FOr Ge. SP sexx fis BS! | Malis ma 
Pritch., p. 858. Heiberg, De Danske Diat., p. 42. Rab. Fl. Eur., 
sect. 1, p. 318.—Amphitetras antediluviana, @. W. Sm., B. D.,Vol. ii. 
p41, El ixivy, fie. "318 a/”. 
Stomachs of Ascidians, Roundstone Bay, Arran Islands, Co. 
Galway. 
Variety a.—On side view, sides parallel.—Amphitetras antediluyi- 
mec: Wms, Be De Voni.; p: £7) ) Rl xdtv., fie. BIG? Hale. im 
Pritch., p. 858, Pl. xi., figs. 21 and 22. 
Stomachs of Ascidians, Roundstone Bay. Arran Islands, Co. Gal- 
way. Malahide. Dublin Bay. Howth, Co. Dublin. Bundoran, Co. 
Donegal. 
Variety b.—With five angles. 
Stomachs of Ascidians, Roundstone Bay, Co. Galway. 
Genus II. Triceratium, Ebr. 
Frustules simple; normally triangular on side view; processes 
short, roundish, springing outwards, at an acute angle to the basal 
plane. 
Triceratium favus, (Ehr.) Marine. 
Striation areolate; areoles hexagonal, large; sides straight or slightly 
convex. 
Kitz. Bac:, p. 139, T. xvii, fig. 11. Wm. Sm., B.D., Vol. i: 
p. 26, Pl. v., fig. 44 ; Supp. Pl. xxx., fig. 44. Ralfs, in Pritch., p. 855. 
Pl. x1., fig. 43. Heiberg, De Danske Diat., p. 41. Rab. Fl. Eur., 
sect. 1, p. 315. 
Stomachs of Ascidians, Roundstone Bay, Co. Galway. 
