216 



WISCONSIN PHYTOPLANKTON 



PLATE 86. 

 All figures x 600. 



Page 



Fig. 1. Arthrodesmus triangularis Lag 133 



Figs. 2-4. Arthrodesmus triangularis var. rotundatus (Racib.) comb. nov. 133 

 Figs. 5-7. Arthrodesmus triangularis var. subtriangularis (Borge) W. & G. 



S. "West 134 



Figs. S-12. Arthrodesmus octocornis Ehr 134 



Figs. 13-14. Onychonema filiforme (Ehr.) Roy & Biss 135 



Fig. 15. Onychonema laeve var. latum W. & G. S. West 136 



Fig. 16. Sphaerososma Auhertianum var. Archerii (Gutw.) W. & G. S. 



West 137 



Figs. 17-18. Sphaerososma excavuta Ralfs 138 



Figs. 19-20. Sphaerososma excavatum var. Westii var. nov 139 



Fig. 21. Sphaerososma exiguum Turn 138 



Fig. 22. Spondylosium planum (Wolle) W. & G. S. West 140 



