PLATE 3. 



Figure 13. Another of the same showing one spore with triradiate ridge 

 and other spores and supposed AlgiB. (X 180.) 



Figure 14. A spore of the same highly magnified. (X 500.) 



Figure 15. A tetrad of the same. (X 180.) 



Figure 16. Horizontal section showing numerous examples of Pila 

 scotica, some in tetrads. (X 130.) 



Figure 17. Upper portion of Figure 16 more highly magnified. (X 180.) 



Figure 18. Vertical section of boghead from Balbardie, Scotland. 

 (X 120.) 



