18 SEA-SHORE LIFE 



these deep-sea creatures belong to tyjDes which once lived in shallow 

 water along onr coasts, but which died out long ago, and are 

 known to us only through their fossils in the rocks. 



Marine animals are much more abundant along or near conti- 

 nental coasts than in the open sea far from land, for we must bear 

 in mind that animal life can subsist only upon plant life and tliat 

 the great food supply furnished by the shallows of a shore are most 

 favorable for the development of a v^aried fauna. 



The great ocean currents, such as the Gulf Stream in the At- 

 lantic, and the Kuroshiwo of the Pacific are the bearers of vast 

 hordes of floating creatures which are thus carried from the tropics 

 far into the temperate regions. Temperature is also a great factor 

 in determining the distribution of marine life. On our own coast, 

 for example, we find that the cold arctic water creeps down the 

 New England coast to Cape Cod, while south of that place the shore 

 water is warmed during the summer by the drift from the Gulf 

 vStream, Accordingly a great number of southern forms extend 

 only as far north as Cape Cod, and similarly many of the arctic 

 creatures can not survive in summer in the wariu water south of 

 til at cape. 



It is even more interesting to see that at Cape Breton, Nova 

 Scotia, we find a numl)er of creatures whose true home is south of 

 Cape Cod, Massachusetts, but which are able to live in the warm 

 water at the mouth of the St. Lawrence, where the Gulf Str(;am 

 approaches the coast for the last time before its final deflection 

 into the midst of the Atlantic. 



So important is temperature in determining the distribution 

 of marine life, that while the creatures of the tropical Atlantic and 

 Pacific on opposite sides of the Globe are, broadly speaking, cpiite 

 similar, those living north of Cape Cod are almost wlioll)' different 

 from those of the Florida coast. 



But the most remarkable condition is seen in the distribution 

 of the creatures of the deep sea, for here the temperature is nearlj- 

 the same everywhere, being only slightly above the freezing point. 

 Accordingly many of these animals range from Arctic to Antarctic, 

 and from Atlantic to Pacific. 



Many forms that live only in deep, cold water, south of Cape 

 Cod come into the shallows on the Maine coast. 



