THE HAUNTS OF LIFE 55 



exploited a great variety of haunts in or on other creatures. 

 In strictness, as we' shall recognize later on, the freshwater 

 haunt should be subdivided into several distinct haunts. 



I. The Shore FAxnsrA 



We must think of the shore-area as nauch more than 

 that stretch of sand and gravel and rock-pool and mud 

 which many of us know so well — ^the happy hunting-ground 

 of child and naturalist alike. The shore-area is much 

 more than the stretch between tide-marks. It includes 

 the whole of the shallow shelf around continents and con- 

 tinental islands, down to a depth of, say, 100 fathoms. It 

 is the area where seaweeds grow. Geographers tell us 

 that, without including the imperfectly known polar areas, 

 the shore-area stretches for over 150,000 miles and has a 

 superficial extent of perhaps nine million square miles. 

 It is therefore an immense area, though it only occupies 

 between 6 and 7 per cent, of the entire sea-surface. It 

 makes up for its relative smallness by the density and 

 variety of its population. 



What strikes us first about the littoral area is that it is 

 the meeting-place of the terrestrial, the freshwater, the 

 pelagic, and the abyssal faunas. Over the marshy ground 

 overflowed at high tides, or over the firm-turfed hnks, or 

 abruptly up the cliffs, or tediously over the seemingly 

 interminable sand-dunes, we pass from the httoral to the 

 terrestrial. Up the long estuary there is often a gradual 

 passage from salt water to fresh, and we notice some ani- 

 mals Hke flounders that don't seem to care which they Uve 

 in. If we take a boat and sail out, or if we swim out in 

 some places, we pass from the httoral to the pelagic area. 

 If, on the other hand, we could walk down the gently 



