Plate 16. 

 Prasiola-composite. 



8. — Cross section of Frasioht horeaUs Reed, unaffected by the fungus. (B. 

 L., oc. 2, obj. 1/6.) 



9. — Cross section of Prasiola composite, showing- slight effect of the fungus 

 upon the alga. (B. & L., oe. 2, obj. 1/6.) 



10. — Similar section from a composite plant more strongly affected. (B. & 

 L., oc. 2, obj. 1/6.) 



11. — Similar section from a composite plant still more strongly affected. 

 (B. & L. oc. 2, obj. 1/6.) 



12. — Similar section from a plant showing nearly if not quite, the maximum 

 effect of the fungus. (B. & L., oc. 2, obj. 1/6.) 



13. — Portion of surface view of Prasiola horeaUs Reed, showing the arrange- 

 ment of the cells. (B. & L., oc. 2, obj. 1/6.) 



14. — Cross section through the center of a perithecium. (B. & L., oc. 2, 



obj. 1/4.) 



Figures 1 and 7 were drawn from nature by Mr. H. N. Bagley. The rest 

 of the figures were drawn with the aid of the camera lucida by the author 

 and prepared for reproduction by Mr. Bagley. 



164] 



