Maskell. — On Neiv Zealand Desmidie*. 



317 



The difference in length of the beaks seems scarcely enough to distinguish 

 them. Ealfs says that the vesicles of 0. setaceum are " none or indistinct." 

 I have certainly observed them here. 



DESCEIPTION OF PLATES XI. AND Xn. 



Figure 1. 



Aptogonum undulatum, side view 





2. 



„ under view 



3, 



„ upper view 



4. 



„ end view 



5. 



Micrasterias rotata, dividing 



6. 



Micrasterias ampiollacea, trifid . . 



7. 



bifid ., 



8. 



„ side view 



9. 



Didymocladon stella, front view . . 



10. 



„ end view . . 



11. 



Dociduim dilatatum 



12. 



„ end of frond 



13. 



,, section 



14. 



„ dividing 



15. 



Closterium selenceuni .. 



16. 



„ end of frond 



17. 



AnMstrodesmus, sp. 



18. 



„ single cell 



19. 



sp. .. 



20. 



,, single cell 



21. 



Triploceras tridentatum 



22. 



„ end of frond 



23. 



)) )) 



24. 



Holocystis incisa, var. . . 



25. 



Sphcerozosma Jiliforme . . 





26. 



Euastrum binale (?) . . 





27. 



Cosmarium margaritiferum 





28. 



M 





29. 



)) 





80. 



Cosmarium ralfsii, empty 





31. 

 32. 

 33. 



Staurastrum (avicula ?) 





Closterium ocerosum, sigmoid 





34. 



Closterium rostratum . . 





35. 



Closterium setaceum 





empty 



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