Clare Island Survey — Fresh-water Algae. 16 61 



DESCRIPTION OF PLATES. 

 Plate I. 



Fig. 



1. Euastrum oblongum Ralfs, after division, one semicell not completely 



developed, x 250. Mulranny. 



2. Reinschiella curvata sp. no v. x 250. Clare Island. 



3. Zygnema leivspermum De Bary. x 300. Dugort. To show that the 



individual cells become physiologically sexual when conjugating. 



4. Oedogonium sp. x 300. Collected in April ; every other cell was often 



firmly encrusted — sometimes many cells successively— with what 

 looked like an oxide of iron ; and in some cases there seemed to be the 

 remains of two successive coatings. — Clare Island. 



5. Closterium angustatum Kiitz., var. asperum var. nov. x 232. Westport. 

 6 Closterium. Toxon West, var. validu?ii var. nov. x 300. Clare Island. 



7. Lyngbya cliarensis sp. nov. x 300. Clare Island. 



8. Tetmemorus Brebissonii (Menegh.) Ralfs, abnormal. x 300. Clare 



Island. 



9. Tetmemorus, abnormal, x 250. Dugort. 



10. Zygospore of Tetmemorus laevis (Kiitz.) Ralfs. x 300. Dugort. 



11. Euastrum, abnormal division, x 300. Clare Island. 



12. do. do., x 300. Dugort. 



13. Closterium eboracense Turn., var. achillense var. nov. x 100. Sraheens 



Lough. 



14. Hicarasterias denticulata Breb. x 250. To show variability of the 



polar lobes. Clare Island. 



