PLATE I 



Fig. I. Part of the boat harbour, Goudier Islet, Port Lockroy, seen at 

 low tide, showing blackish staining of the rocks caused by Verrucaria 

 psychrophila M. Lamb. Phot. I.M.L., 23. iv. 1944. 



Fig. 2. Verrucaria serpuloides M. Lamb, forming black patches on sub- 

 merged granodiorite rocks off the shore of Goudier Islet, Port 

 Lockroy, belowthe lowest ebb-tide level. (Under-waterphotograph.) 

 Phot. I.M.L., 19. X. 1944. 



Fig. 3. Close-up view of Verrucaria psychrophila M. Lamb, on a boulder 

 in the boat harbour of Goudier Islet, Port Lockroy, at low tide. 

 Phot. I.M.L., 4. xii. 1944. 



