t 

 8 BIOLOGICAL SOCIETY OF WASHINGTON. 



currents, like the Gulf Stream, may reach, for a small part of 

 their course, the ocean floor and sweep it clean of sediment and 

 detritus, if not entirely of living beings. Such mechanical 

 effect as is produced must be of a rather stead}- and uniform 

 nature for considerable periods and in no respect resemble the 

 crushing and grinding which take place on every exposed beach 

 on which the sea rolls up. In fact, regarded as individuals, 

 the mollusks in the path of the Gulf Stream and other great 

 currents, have little or nothing to fear from the mechanical at- 

 trition which plays so large a part in the shallows. On the 

 other hand wherever the force of the stream is not sufficient to 

 sweep the bottom clean, the supplies of oxygen and food 

 brought by it to the colonies along its path so far exceed the 

 normal for quiet waters, that the animals thus favored flourish 

 and multiply in a manner never seen in quiet deeps. 



The influence of darkness upon the inhabitants of the 

 Abyssal Region has often been expatiated upon. The absence of 

 visual organs or their preternaturally excessive development 

 beyond the normal of the groups to which the individuals 

 belong is evidence enough that the deeps are markedly darker 

 than the shallows. But this evidence proves too much for the 

 claim that the deeps are mathematically dark. Whatever 

 notions may be entertained or conclusions deduced by the 

 physicist from the premises, the presence of large and remark- 

 ably developed eyes in man}' abyssal animals shows that light 

 of some sort exists even on the oceanic floor. It is inconceiva- 

 ble that these organs should be developed without any light 

 and if the experiments and reasoning of the physicist result in 

 the apparent demonstration of absolute darkness in the depths, 

 the facts of nature show that in his premises or his experiments 

 there lurks some vitiating error. It is ridiculous to suppose 

 that the phosphorescence of certain animals in the deep sea 



