172 STUDIES IN INSECT LIFE, ETC. 



Before we consider what really is at the bottom 

 of the ocean, let us for a moment try to consider 

 what we should see were it possible to " gather 

 up the sea/' Suppose we imagine that the sea 

 " is gathered up," and that we start from the 

 west coast of Portugal or Spain to walk or bicycle 

 or motor across the bed of the Atlantic Ocean. 

 At first we should progress along a shallow in- 

 cline, passing through a region " peopled " with 

 sea-anemones, polychromatic worms, limpets, 

 mussels, periwinkles, dog-whelks, star-fish, sea- 

 urchins and small Crustacea, certain inshore fishes, 

 and certain seaweeds. Proceeding ever west 

 towards the depths of the Atlantic we should 

 soon lose sight of the seaweeds, and the nature 

 of the invertebrate fauna and of the fish would 

 change. The sea-floor would cease to be rocky, 

 gravelly, or stony, and change into soft muds or 

 oozes of various colours. The constituents of 

 these deposits are derived from the neighbouring 

 land washed down by rivers and streams and 

 carried out to sea by the fresh water. Sooner 

 or later, however, we should pass beyond the 

 line which earth-born deposits reach, and the 

 limits of this area have been very aptly named 

 by Sir John Murray " the mud line." This mud 



