ORGANS OF HEARING. 185 



ensation : it appears to me more plausible to infer 

 hat the antennae serve for the perception of sounds. 

 Phis opinion is founded partly on the analogy of what 

 nccurs in the larger animals, who prick up their ears 

 mder similar circumstances in order to hear better ; 

 nd partly because, on following the progress of 

 legradation in the organ of hearing from the first 

 f the vertebrate animals (Vertebrata), we arrive 

 igain in the last analysis at the antennae of articu- 

 ated animals, by a sort of transition occurring in 

 he lobster and craw-fish (Astacus), a genus in 

 rhich this organ occurs in the simplest form, corn- 

 ered with that of superior animals." 



QThe author here goes into several details illus- 

 rative of this last statement, which we shall omit, 

 ,s of less weight than what follows.] 



' The solidity of the envelope of antennas renders 

 hese organs well adapted to undergo the same 

 ibrations as the air, in the same manner as the 

 trings of an ^Eolian harp vibrate and emit various 

 ounds, according as they are differently struck by 

 he air. In this view, however, we might infer 

 hat nature would have made antennas in the form 

 f rods, consisting of a single piece, in order that 

 hey might be more susceptible of vibrations ; but 

 t ought to be considered, that these organs would, 

 >y such a conformation, have been much exposed 

 o breaking, while, in consequence of their jointed 



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