PRESIDENTIAL ADDRESS. 



61 



fails to reach the lichen patches marking the advance limit 

 of the terrestrial world. Between this lowest life of the 



Fig. 24. Sargassum tristichum, a brown sea weed about a foot high, 

 associated with Eklonia. 



land and highest of the sea, a fairly wide vacant space here 

 intervenes. During neap tides in hot weather the highest 

 small rock pools evaporate and their basins are lined with 



