222 WISCONSIN PETTOPLANKTGN 



PLATE 37. 



Page 



Fig. 1. Crucigenia apiculata (x 1000) 146 



Fig. 2. Crucigenia tetrapedia (x 1000) 147 



Fig. 3. Crucigenia fenstrata (x 1000) 148 



Fig. 4. Crucigenia Lauterbornei (x 1000) 148 



Figs. 5-6. Tetrastrum staurogeniaclorme, (x 1000) 149 



Figs. 7-11. Tetradesmus wisconsinensis (x 1000) 150 



Figs. 12-14. Scenedesmus obliquus (x 1000) Ibl 



Figs. 15-17. Scenedesmus dimorphus (x 1000) 151 



Figs. 18-20. Scenedesmus bijuga (x 1000) 152 



