J54 WISCONSIN PHYTOPLANKTON 



PLATE 55. 

 All figures x 400. 



Page 



Figs. 1-2. Pleurotaenium truncatum (Be Breb.) Nag 16 



Fig. 3. Pleurotaenium trochiscum var. tuberculatum var. nov 17 



Fig. 4. Docidium undulatum Bail 18 



Figs. 5-6. Triploceras gracile Bail 1^ 



Figs. 7-9. Triploceras verticillatum Bail 19 



Fig. 10. Tetmemorus Brebissonii (Menegh.) Ealfs 20 



