xli 



EXPLANATION OP PLATE II., 



ILLUSTRATING 



MR. ARCHER'S PAPER ON DOCIDIUM (pp. 83, 84), AND ON STEPHA- 

 NOSPILERA (p. 151); AND ADMIRAL JONES'S PAPER ON SPIRAL 

 VESSELS IN EVERNIA PRUNASTRI (p. 117). 



Fig. 1. Triphceras (Docidium) gracile (Bailey). 



„ 2. Docidium, Kayeii (Arch., sp. nov.). 



,, 3. Stephanospliatra pluvialis (Cohn), showing the primordial 



cells assuming the amceboid condition. 



„ 4 to 6. The primordial cells free, and having quite assumed the rep- 

 tant amoeboid condition. 



„ 7 to 10. Spiral vessels found in the thallus of Evernia prunastri. 



