THE IMPENETRABLE SEA 



The narwhal has never been known to charge and 

 pierce the hulls of ships with his mighty weapon, as the 

 swordfish does, although the narwhal's tusk might seem 

 to be as well-adapted to the purpose. When first intro- 

 duced into Europe as trophies, the tusks of narwhals 

 were accepted as the horns of mythical unicorns, and 

 as proof of the existence of such creatures. For a con- 

 siderable time they were highly prized as talismans, and 

 for their supposed medicinal qualities. 



It is probable that more ''magic" has accumulated 

 around the sea-unicorn's tusk than around the appendage 

 of any other animal of land or sea. Queen Elizabeth I 

 was graciously pleased and delighted to accept a nar- 

 whal's tusk from Sir Martin Frobisher on his return from 

 a valiant though vain dash into the Arctic regions. That 

 it was apparently the only trophy he brought back 

 seemed to make it all the more precious as a souvenir of 

 that unsuccessful voyage. 



We have examined only a few of the wonderful 

 creatures which perform their antics on the sea's surface. 

 The entire surfaces of the vast oceans, and of the world's 

 lakes, rivers and streams, are alive with fishes, birds and 

 insects in continuous motion: millions upon millions of 

 living creatures whose lives and habits are curiously 

 inter-related, and whose combined activities contribute 

 to the mysterious progress of mankind itself 



Despite the nose-protrusions of sharks into the atmo- 

 sphere, and the occasional cavortings of whales above 

 the waves of the sea, such creatures are really under- 

 water ones, and cannot be done justice to among surface 

 creatures. They will receive special attention in later 

 chapters, as will planktonic creatures — at the other ex- 

 treme in size — when we go down into the deeps of the 

 oceans, and (as far as we can) into the knowledge that 

 has accumulated about such life-forms through the ages. 



By far the larger proportion of such knowledge, how- 

 ever, is concerned with fish and other creatures which 



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