A LIVING MAELSTROM. 213 



The fluid is whirled round and round with a velocity 

 which ever increases as the diminishing spiral curve 

 approaches the centre of the vortex. 



Thus, according to a law in physiology, that the 

 lower the rank of an organism in the scale of being, 

 the less of differentiation we find, the less of specialty 

 in the assignment of function to organ, the two offices 

 of procuring food and of breathing, which in the 

 Mussel are performed by two distinct sets of organs, 

 are in the inferior Tubulipora appropriated to one. 

 The whirlpool, which ever brings fresh particles of 

 water to the surfaces of the filaments, that the oxygen 

 which they carry may be in succession absorbed by 

 the blood which penetrates into these organs, brings 

 something else. Whatever atoms of organic substance, 

 the dissolving constituents of some decomposing ani- 

 mal or vegetable, whatever roving animalcules, what- 

 ever spores of alg^e, chance to come within the margin 

 of this Mahlstrom, they are sucked into its circle, and 

 are then inevitably hurled round in its embrace ; at 

 every revolution approaching nearer to that open gulf 

 at the bottom, that living grave, into which, one by 

 one, they descend with a gurgle and a gulp. 



And this is how the Tubuliporce, and hundreds 

 more of creatures of like kidney, procure their dinner. 



