142 MARINE ANIMALS OF MASSACHUSETTS BAY. 



fatal to other creatures. The same is true of any stony beach or 

 rocky shore not more than a quarter of a mile in length ; it gives 

 us an idea of the animal population on any similar coast of great- 

 er extent. 



These correspondences are of course modified by differences 

 in climatic conditions. The animals on a sandy beach or a rocky 

 shore, on the coast of Great Britain, for instance, are not absolute- 

 ly identical with those of a sandy beach or a rocky shore on the 

 coast of New England, but they are more or less nearly related 

 to them. Naturalists refer to this reiteration, all the world over, 

 of like organic combinations under similar circumstances, when 

 they speak of " representative species." The aggregate result is 

 the same, though the individual forms are slightly modified. 

 And here lies one secret of the uifinite variety in nature, by 

 which the old seems ever new, and the same thought has an eter- 

 nal freshness and originality, endlessly repeated, yet never hack- 

 neyed. 



In this sense our bay present's, on a miniature scale, a variety 

 of physical and organic combinations, which may be compared to 

 those more extensive divisions in the geographical distribution of 

 animals and plants, called by naturalists zoological or botanical 

 provinces or districts, the animal and vegetable populations of 

 which are technically designated as their faunae and florae. Such 

 organic realms, as we may call them, have long been recognized 

 on land, and the most extensive among them are easily distin- 

 guished. No one will fail to recognize the tropical zone, with its 

 royal dynasty of palms and all the accompanying glories of a trop- 

 ical vegetation, its birds of brilliant plumage, its large Mammalia, 

 lions, tigers, panthers, elephants, and its great rivers haunted by 

 gigantic reptiles. Nor is the representation of vegetable and ani- 

 mal life less characteristic in the temperate zone, where the oak 

 is monarch of the woods, with all his attendant court of elms, 

 walnuts, beeches, birches, maples, and the like, where birds of 

 more sober hues, but sweeter voices, take the place of the bril- 

 liant parrots and many-tinted humming-birds of the tropical 

 forest ; while buffaloes, bears, wolves, foxes, and deer represent 

 the larger Mammalia. In the arctic zon6, though marked by 

 peculiar and distinctive features, vegetation has dwindled to a 



