LIFE IN THE OCEAN CLARK 381 



The long slender snakelike sea serpents are the writhing arms of 

 which the expanded ends look something like a head. 



Another common sea serpent on the New England coast is a com- 

 posite picture of two basking-sharks which, swimming one behind 

 the other, sometimes appear as a single creature nearly 100 feet in 

 length. Still other sea serpents are based on porpoises or dolphins, 

 and on large tropical fishes. 



Other inhabitants of the twilight zone are strange fishes, espe- 

 cially the ribbon fishes, which may reach a length of over 20 feet 

 with a height of a foot or less and a thickness of only an inch or 

 two at the broadest part. Ribbon fishes and their close relatives, 

 the oar fishes, are found floating dead or washed up on the beaches 

 in all parts of the world, and seem not to vary from one locality 

 to another. Very young ones, queer looking things, are sometimes 

 taken in tow-nets. 



THE OCEAN AND THE LAND 



On land there is vegetation everywhere except in the most arid 

 regions, and even there a heavy rain is immediately followed by the 

 appearance of plants of many kinds. The plants are always the 

 most conspicuous living features of every landscape; but they grow 

 only on the surface of the land, rooted in the soil or, more rarely, 

 attached to some support or floating in the water. 



In the open sea no plants are ever visible, save for an occasional 

 dying rockweed torn from its moorings, though sometimes streaks 

 and clouds indicate masses of diatoms or other minute plants in- 

 dividually invisible to the unaided eye. The visible life of the sea 

 is entirely animal; but the microscopic plants, all of which drift 

 freely about, exist in incredible numbers and occupy a broad stratum 

 reaching a maximum of about 650 feet in thickness in the clearest 

 waters of the Tropic seas, but decreasing to a much lesser thickness 

 north and south where the water is less transparent and where the 

 light is less. 



Very few animals feed directly upon the sea plants, and of these 

 only the minute crustaceans are of first importance. These, pos- 

 sessed of only feeble swimming powers, drift aimlessly about and 

 may be said to furnish the chief, though a purely secondary, basis 

 of marine life ; though animals, they are to the ocean what the green 

 plants are to the land. 



In contrast to land animals, most of the smaller and many of the 

 fairly large marine animals, such as the jelly fishes and the younger 

 stages of such fishes as the ribbon fishes and the eels, are more or less 

 transparent, some quite so, looking like glass models of themselves. 



Never put your fingers into the catch of a tow-net haul without 

 first knowing what is there. Once I was trying to catch a paper 

 1454—25 26 



