» 



O'Meara — Itqiort on the Irish Diatomacecc. 277 



all cases substantiated by obseryation, but because it seems the most 

 satisfactory. And not being in a position either to sustain or refute 

 the assiimption, I consider the proper course is to leave them as they 

 stand. 



Genus I. Amphiteteas, Ehr. 



Prustules concatenate ; cubical ; processes springing from each angle 

 of the valve short. 



Amphifetras 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.) 



Kutz. Bac, p. 135, T. xix. fig. 3 ; T. xxix. fig. 86. Ealfs, in 

 Pritch., p. 858. Heiberg, De Dauske Diat., p. 42. Eab. El. Eur., 

 sect. 1, p. 318. — Amphitetras antediluviana, /3. W. Sm., B. D.,Yol. ii. 

 p. 47, PI. Ixiv., fig. 318 a'". 



Stomachs of Ascidians, Eoundstone Bay, Arran Islands, Co. 

 Galway. 



Variety a. — On side view, sides parallel. — Amphitetras antediluvi- 

 ana, Wm. S., B. D., Vol. ii., p. 47, PI. xliv., fig. 318. Ealfs, in 

 Pritch., p. 858, PL xi., figs. 21 and 22. 



Stomachs of Ascidians, Eoundstone Bay. Arran Islands, Co. Gal- 

 way. Italahide. Dublin Bay. Howth, Co. Dublin. Bundoran, Co. 

 Donegal. 



Variety h. — With five angles. 

 Stomachs of Ascidians, Eoundstone Bay, Co. Galway. 



Genus II. Thiceeatium, Ehr. 



Erustules simple ; normally triangular orC side view ; processes 

 short, roundish, springing outwards, at an acute angle to the basal 

 plane, 



Triceratimn faius, (Ehr.) Marine. 



Striation areolate; areoles hexagonal, large; sides straight or slightly 

 convex. 



Kiitz. Bac, p. 139, T. xvii., fig. 11. Wm. Sm., B. D., Vol. i., 

 p. 26, PI. v., fig. 44 ; Supp. PL xxx., fig. 44. Ealfs, in Pritch., p. 855. 

 PL xi., fig. 43. Heiberg, De Danske Diat., p. 41. Eab. El. Eur., 

 sect. 1, p. 315. 



Stomachs of Ascidians, Eoundstone Bay, Co. Galwny. 



