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tion as do the concretions. Others, in regions 

 that apparently have been subjected for a longer 

 time to wave action, contain no such boulders. 



According to their location, illumination, 

 and other factors to which forms must adapt 

 themselves, the pools contain various plant and 

 animal forms. 



In the pools with overhanging edges, eel- 

 grass occurs in great abundance, the rock layers 

 forming a point of attachment for the holdfast. 

 Those pools exposed to the lower tides, and 

 the best conditions of illumination and temper- 

 ature, exhibit the greatest variety and number 

 of life forms. 



Generally, though not always, the greatest 

 variety and number occur in the largest pools. 

 In one pool, 3 x 2 x 2^ feet were found the 

 following animal forms: mussels, goose-neck 

 barnacles, acorn barnacles, chitons, limpets, 

 sea-robins, sea-urchins, sea-anemones, snails, 

 and hermit crabs. The chitons and the sea- 

 robins exhibited protective coloration, assuming 

 the color of the rocks, which varies from dark 

 red, to light pink and green. These colors 

 are due to incrusting algae. 



