224 The Fish World at Home. 



played a very important part among the pristine* inhabitants 

 of the globe. In our own times the waters cover two-thirds 

 of the earth, and within certain limits they are thickly peopled 

 by the finny race. The subaqueous land is as diversified as the 

 subaerial, and if we could roam over the sea-bottom as we do 

 over the dry surface, we should find its varieties of contour as 

 strongly marked. In some spots we should discover sedimen- 

 tary plains, in others elevated table-lands and lofty mountain 

 chains, while the vegetation would be plentiful, scarce, or 

 absent, according to laws analogous to those which affect ter- 

 restrial plants. In some situations, where the water is shallow 

 and the soil appropriate, we should come upon green meadows 

 of the common Zoster a marina; on rocks in deeper water we 

 should find groves and forests of the oar-weed {laminaria), 

 and other tree-like algge; and if in our own climate these 

 seldom exceeded twelve or fourteen feet in length, we need 

 only go to the coast of North America to find a tangle, named 

 nereocystis, with stems three hundred feet long, and floats like 

 huge casks, crowned by tufts of prodigious leaves, among 

 which the sea-otter makes his lair. On dry land the most 

 numerous population is seated at, or near, the sea-level, or at 

 what we may call the bottom of the aerial ocean which enfolds 

 our globe; except on the Mexican plateaux, animal forms become 

 scarce after an elevation of a few thousand feet, while extreme 

 mountain heights are solitudes scarcely broken by the sound or 

 sight of life. In the watery regions some differences occur. 

 There, the mountains, instead of being deserts, present condi- 

 tions which offer some analogies to the sea-level surface of the 

 earth. Light is abundant in such situations, and the moving 

 waves carry to the limited depth a more ample supply of air. 

 Here then life abounds, and it is the lowest valleys and plains 

 of the ocean beds, which correspond with the subaerial moun- 

 tain-peaks, in affording a very restricted accommodation for 

 living beings. Recent discoveries in deep sea dredging modify 

 old statements about the total absence of life in the dark and 

 profound recesses of the sea; but at any rate, so far as the 

 higher forms are concerned, dense populations occur only at 

 moderate depths. 



The subaqueous scenery of our own shores exhibits on a 

 limited scale the varied aspects to which allusion has been 

 made; but it nowhere sinks to remarkable depths. In the 

 North Sea, between us and Norway, 140 fathoms is said to 



* " No vertebrate animal higher in the scale than fishe9 is as yet certainly 

 known to have been found in any rock of Devonian age. In fact, until demon- 

 strative stentigraphical evidence of the Devonian age of the red known Elgin beds 

 is obtained, the bearing of the pala;ontological evidence against that conclusion is 

 too strong to allow of its being entertained." — Professor Huxley, Memoirs of 

 Geological Survey, Decade X. 



