THE SEA SHORES 1 83 



small birds, which here are very shy. In the harbors of the 

 east the kites, soaring over the water on the watch for scraps, 

 look strange to us, accustomed as we are to gulls alone. The 

 condor and the California vulture frequent the beaches more 

 or less, and the nests of the latter often contain mussel shells. 

 Two of the cormorants, one, now extinct, but formerly common 

 in the Commander Islands, the other living in the Galapagos 

 group, one auk, formerly abundant on the north Atlantic coasts 

 but now extinct, and all the penguins, are flightless. 



Of other sea-coast creatures there are the seals, which live 

 on fish, the walrus, which lives on mussels, and the sea-otter, 

 now very rare, which eats largely, if not mainly, sea-urchins. 

 The sea-snakes, true snakes and poisonous, yet true sea animals, 

 most of them more helpless on land than eels, the sea-weed- 

 eating iguana of the Galapagos, and the coypu of the inlets 

 of southwestern South America also deserve mention. But 

 the most curious of all the sea-coast creatures is the large fish- 

 eating bat of the Caribbean region which smells strongly of 

 musky fish oil and is abundant at St. Vincent. This bat spends 

 the day in chinks and crevices in the sea cliffs which one would 

 think much too small for it. I once fired both barrels of a 

 i2-bore gun into a narrow crack 15 feet or so above the water 

 and secured no less than 62 of them. 



What is the vegetable basis of this abundant coastal life? 



On our north Atlantic coasts and on the coasts of Europe 

 this comes from four main sources. 



I. Vegetable detritus, or the more or less decayed fragments 

 of the plants growing on the bottom, the sea-weeds and the 

 eel-grass, suspended or dissolved in the water, lying on the 

 bottom, or mixed with the bottom mud. 



According to very careful investigations which have been 

 carried on in Denmark all the bivalve molluscs, two snails, all 

 the sea-cucumbers, sipunculids, cumaceans, sea-squirts, ostra- 

 cods, polyzoans, sponges and foraminifera, and the balano- 

 glossids and cephalochordates, as well as the beach-fly larvae, 

 are purely detritus feeders; the great mass of material in their 



