XXVI INTRODUCTION. 



animals. " Our woods on shore," Mr. Darwin says, 

 ^^ do not harbour so many animals as the woody 

 regions of the ocean, where the sea- weed groves, 

 rooted to the shallows, or the Fuci, detached by 

 waves and currents, supported by air-cells, and 

 swimming" free, unfold their delicate arms and 

 branches , " and furthermore he affirms, ^^ that if 

 the immense sea-weeds of the Southern Ocean 

 were removed by any cause, the whole Fauna of 

 these seas would be changed," The fact of pilch- 

 ards on the coasts of Cornwall having forsaken the 

 shallow water within coves, where they were for- 

 merly caught in great abundance, and are now but 

 rarely seen, is fully proved by the investigations of 

 the Messrs. Couch to be attributable entirely to the 

 practice of the farmers, who cut the sea- weed from 

 the rocks, for the purpose of manuring their lands. 

 By this means they destroy all the small Crustace- 

 ans inhabiting these immature marine forests, feed- 

 ing on the algse, and as they constitute the principal 

 food of the pilchards, these leave their old haunts 

 for more favourable situations. It is supposed by 



