CusHMAN : Zygospores of desmids 229 



Hxplauatlon of plates 7 and 8 



r 



Plate 7. X 220 



Figures 1-3. Closterium Dianae Ehrenb. 

 Figures 4-6. Closteriwn lineatum Ehrenb. 

 Figures 7, 7^, Micrasterias papUlifera Br^b. 



Figure 8, Penium Clevei crassum W. & G. S. West. 



Figure 9. Cosmariuvi pseudoorbiculatuvi sp. nov. 

 Figures 10, \oa. Sphaerozosma readingensis sp, nov. 



Plate 8. X 45^ 



Figure ii. Staurastrum brtvispiniim basidentatiim var. nov. 



Figures 12, 13. Staurastrtvn brevispinum Breb. 



Figure 14, Statirastr-um dilaiatum Ehrenb. 



Figures 15, 16. Staurastrnm gmnde glabrtim var. nov. 



Figure 17. Staurastrum grande Bulnh. 



Figures 18, iS^z. Staurastrum poiytrickum readingense v2iX, nov 



Figures 19, 19^. Staurastrum eiistephanum (Ehrenb.) Ralfs. 



