BELOW THE TIDEMARK 



THANKS to the moon and her tides we gain access twice a 

 day by the sea-shore to the margin of that hidden region out 

 of which it is believed that life came, and where it is fostered 

 in such strange and multifarious forms. It is only a strip 

 perhaps averaging a hundred and fifty yards wide that the 

 sea daily bares, with a vertical depth as ridiculously dispro- 

 portionate to the size of the Atlantic ; and yet it is a world 

 almost entirely different from our own, and full of unfamiliar 

 shapes of life. 



The herbs of the sea have no flowers, with the technical 

 exception of the light green ribbon-grass which grows thickly 

 in muddy shallows, and is a favourite food of the widgeon. 

 Some of the seaweeds are like liverworts, and others like 

 lichens, which are partly seaweeds themselves ; but most sea 

 weeds are quite unlike any form of dry-land vegetation. Where 

 the tide rolls up at high-water mark a long bolster of tangled 

 drift, the commonest seaweed is the bladder-wrack, with its 

 rows of bubbles or blisters. It is common on almost any rock 

 that the tide lays bare ; and it belongs to the same frontier 

 of the ocean kingdom that we are allowed to tread. Bladder- 

 wracks are seaweeds of the surface, and their bladders enable 

 them to float at the level which suits them, whether they 



