210 WISCONSIN PHYTOPLANKTON 



PLATE 25. 



Page 



Fig. 1. Tetracdron victorieae var. major (x 1000) 119 



Figs. 2-3. Tetracdron verrucosum (x 1000) 119 



Figs. 4-7. Tetraedron caudatum (x 1000) 120 



Figs. 8-12. Tetracdron caudatum var. longispinum (x 1000) 120 



Figs. 13-17. Tetraedron pentaedricum (x 1000) 120 



Fig. 1?. Tetraedron hastatum (x 1000) 121 



Figs. 19-21. Tetracdron hastatum var. palatinum (x 1000) 121 



Figs. 22-24. Tetraedron constrictum (x 1000) 122 



