■264 Proceedings of the Royal Irish Academy. 



(d). Cellules radiate at the margin, linear in the central portion. 



Coscinodiscus Jimlriatus, (Elir.) llarine. 



Cellules hexagonal ; small ; in the central portion of the disk 

 tirrangcd in lines crossing in quincunx ; towards the margin radiate ; 

 smaller towards the margin. 



Ehr. Mic. Ealfs, in Pritch., p. 829. 



Stomachs of Ascidians, County Clare. 



(e.) Cellides arranged variously. 



Coscinodiscus marginatus, (Ehr.) ITarine, 



Cellules large, hexagonal, arranged in irregularly curved lines, 

 with a distinct narrow strongly costate margin. 



Ehr. Hie. Ealfs, in Pritch., p. 829. Weisse, Eecherches Micro- 

 scopique sur le Guano, Bui. de I'Academie Imp. de St. Petersburg, 

 T. xii., p. 122, PI. i., fig. 21. 



Stomachs of Ascidians, Eoundstone Bay. AiTan Islands. Stomachs 

 of Ascidians, Broadhaven Bay, Co. Galway, 



Coscinodiscus lineatus, (Ehr.) Maiine. 



Cellules rounded, arranged in oblique, parallel lines. 



Ehi'enberg, in his Microgeologie, gives several figures under this 

 name. One of them, T. xxii., fig. 6 a. b., seems scarcely assignable to 

 the genus Coscinodiscus, inasmuch as it is furnished with a marginal 

 circlet of nodules. Besides this there are two other forms, quite dis- 

 tinct : one in which the striae are lineai', to be immediately described ; 

 the other, the present form, which is fuiTiished with cellules as 

 described above. 



Ehi'. Mic. Kiitz. Bac, p. 131, T. i., fig. 10. Ealfs, in Pritch., 

 p. 830. 



Halahide. Monkstown. Dredgings in Bay, Co. Dublin. Sea- 

 weeds, "Wicklow. Breaches near Newcastle, Co. "Wicklow. Bannow, 

 Co. Wexford. Stomachs of Ascidians, Co. Clare. Stomachs of Asci- 

 dians, Eoundstone Bay, Arran Islands, Co. Galway. 



Coscinodiscus Ehrenhergii, N. S. Marine. 



Disk striate. Strise linear, in two series, crossing each other 

 obliquely. (PI. 26, fig. 24.) 



This is the form described by Ehrenberg as Cos. lineatus, Mic, 

 T. xxxv.,_ A. 17, fig. 7; T. XXXV., A. 16, fig. 3. Weisse, Bui. de 

 I'Academie de St. Petersburg, Tom. xii., PI. i., fig. 20 a, 



Malahide. Piles of wooden bridge, Dollymount, Co. Dublin. 

 Stomachs of Ascidians, Eoundstone Bay, Co. Galway. 



