214 MR. W. WEST ON THE FRESHWATER 



Plate XX. {continued). 



Fig. 11. Euastrum verrucosum, Ehrnb., Tar. coarctatum, Delp., forma. 400/1 



12. „ elegans, Kuetz., forma. 625/1. 



13. „ pyramidatum. West. 400/1. 



14. „ binale, Ralfs, forma hians, West. 600/1. 



15. „ ,, „ *subelobatum, West. 400/1. 



16. „ crassangulatum, Boerg., var. ornatum, West. 400/1. 



„ denticulatum, Gay, var. granulation , West. 600/1. 



17. 



18. „ Turnerii, West. 400/1. 



19. Cosmarium tatricum. Racib., var. sphcsruliferum, West. 400/1. 



20. „ eductum, Roy et Biss., var. angustaturn, West. 625/1. 



21. „ pseudopyramidatum, Lund, forma subrect angular is, West 



400/1. 

 22-23. „ succisum, West, 400/] . 



24. „ pygmceum, Arch. 400/1. 



25. „ tenue, Arch. 400/1. 



Plate XXI. 



1. Cosmarium venustum, Rabh., var. hypohexagonum, West. 400/1. 



2. „ perpusillum, West. 600/1. 



3. „ Uegnesii, Reinsch, var. tritium, 600/1. 



4. „ Subdanicum, West, a, 600/1 ; b et c, 400/1. 



5. „ NfOtattii, West 600/1. 

 6. 



7. 



)t 



it 



West. 400/1. 



latum. West, a, 600/1 ; 



400/1 



8. „ spharoideum, West, a, b, et c, 400/1 ; a', 600/1. 



9. „ subpunctulatum, Nord., var. Boergesenii, West. 625/1. 



10. „ Amellii, Boldt, forma compressa, West. 625/1. 



11. H synthlibomenum, West. 625/1. 



12. ,, Botrytis (Bory), Menegh., var. mediolceve, West. a, *, et c y 



400/1 ; a', 600/1. 



13. „ confumm, Cooke, *ambiguum, West, a, b, et c, 600/1 , 



a\ 400/1. 



14. „ Boeckii, Wille, *bipapillatum. West. 400/1. 



15. n isthmium, West, forma hibernicum, West. 400/1. 



16. 

 17. 



>! 



M 



West. 400/1 



West. 400/1 



18. „ obeuneatum, West, a, 600/1 ; e, 400/1. 



19. „ Hibernicum, West. 400/1 



Plate XXII. 



West. 400/1 



2. 

 3. 

 4. 

 5. 

 6. 



antilojxBum , Kuetz., forma. 400/1. 



West. 400/1 



West. 400/1 



West. 400/1 



West. 400/1. 



