16 62 Proceedings of the Royal Irish Academy. 



Plate IT. 



Fig- 



15. Closterium Lunula (Mull. )Nitzsch. To show apices, x 22S. Dugort. 



16. Closterium eboraeense Turn. var. achillenst var. nov. To show apices. 



x 420. Sraheens Lough. 



17 &18. Mierasterias deutienliifa Breb., after division, the new seniieells not 

 completely developed ; one with abnormality of the polar lobe, x 250. 

 Clare Island. 



19. Gosmarium Italfsii Breb., var. rotundatum var. nov. x 250. Westport. 



20. do. do. var. montanttm Eacib. x 300. Dugort. 



21. Emiotiii lit nan's (Ehrenb. ) Grun. var. emarginatovelida var. nov. x 500. 



Dugort. 



22. Navicula peregrina Kiitz., var. producta var. nov. x 300. Clare Island. 



23. To illustrate the same as Fig 3. x 300. Dugort. 



'2i. Zygnema sp. with a distinct mucous investment, as in Byaiotheca d milieus, 

 x 300. Clare Island. 



