ORGANS OF HEARING, 185 
sensation : it appears to me more plausible to infer 
that the antennz serve for the perception of sounds. 
This opinion is founded partly on the analogy of what 
occurs in the larger animals, who: prick up their ears 
under similar circumstances in order to hear better ; 
and partly because, on following the progress of 
degradation in the organ of hearing from the first 
of the vertebrate animals (Vertebrata), we arrive 
again in the last analysis at the antenne of articu- 
lated animals, by a sort of transition occurring in 
the lobster and craw-fish (Astacws), a genus in 
which this organ occurs in the simplest form, com- 
pared with that of superior animals.” 
[The author here goes into several details illus- 
trative of this last statement, which we shall omit, 
as of less weight than what follows. ] 
“ The solidity of the envelope of antennee renders 
these organs well adapted to undergo the same 
vibrations as the air, in the same manner as the 
strings of an Adolian harp vibrate and emit various 
sounds, according as they are differently struck by 
the air. In this view, however, we might infer 
that nature would haye made antenne in the form 
of rods, consisting of a single piece, in order that 
they might be more susceptible of vibrations ; but 
it ought to be considered, that these organs would, 
hy such a conformation, have been much exposed 
to breaking, while, in consequence of their jointed 
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