1GO FUNCTIONS AND INSTINCTS. 



of the visible creation, and therefore an infinite 

 host of invisibles was necessary to remove them 

 as nuisances. 



But the principal point, and that in which 

 their utility most evidently appears, is their fur- 

 nishing a principal portion of the food of innumer- 

 able animals of a higher order than themselves. 

 Those infinite armies and forests of locomo- 

 tive and fixed Polypes, that give to the ocean 

 one of the features that distinguish earth, have 

 their mouths surrounded with tentacles, when 

 expanded assuming the appearance of so many 

 blossoms, with these they collect their food, 

 which, amongst the more minute ones, con- 

 sists often of our Infusories. A single stem of 

 these compound animals, having often innumer- 

 able oscula or mouths, requires a vast supply of 

 food ; others equally compound, as the Ascidians 

 or Alcyons, by alternately absorbing and expelling 

 the sea water, draw in with it a supply of animal 

 food, consisting, in part, of the creatures in ques- 

 tion, which abound in the oceanic waters ; some 

 of these have a common organ for this purpose, 

 and in others each individual of the system is 

 fitted with one ; the Molluscans and an infinity 

 of the smaller inhabitants of the ocean, doubt- 

 less also derive a considerable portion of their 

 nutriment from them, the minute Crustaceans 

 probably do the same, and many insects, 

 whose larvae inhabit the waters, some by pro- 



