I 20 5 ] 
The ftru&ure of the wind* pipe of all thefe is f> 
fingular and fo little known, that I thought a proper 
notice of the fubjedt would be agreeable to the Society,, 
and very fit to be recorded together in the Tranfadti- 
ons, if it be approved of (and will be a fuitable 
fequel to thofe confederations upon amphibious ani- 
mals) ; which I fhall illuftrate with drawings, to ren- 
der their defcription the more intelligible. 
The wild fwan is fomewhat fmaller than the tame 
this inhabits frefh rivers in land, while the wild 
one 
one always reforts great lakes and arms of the fea. 
Thefe are two diflindt fpecies, the river fwan, and the 
fea or wild fwan ; and yet it has been fuggelfed, that 
the latter might become as tame and familiar as the 
others, if they were brought up young: and hence 
they were luppofed to be the fame. But this won- 
derful flru&ure of the afpera arteria (hews that they 
are different, for the river fwan has it not ^ although a 
very modern author, who is certainly as well vei led in 
natural hillory as any one whatever, has thefe re- 
markable words; “ All the writers on birds ; fays he, 
tc have defcribed the fwan : they have called it cygnus 
domefticus, and cygnus ferus, diftinguifbing it in 
its wild and familiar date into two fpecies, but this 
is idle and unneceffary : the bird is wholly the 
“ fame in both.” 
It will be feen, however, by the defcription of the 
part mentioned, they cannot be the fame fpecies; for, 
belides this formation of the pipe, Mr. Edwards 
fhews their heads to be very different alfo.. 
In the general run of birds, the afpera arteria is 
nearly ftrait; that is, having no plications, but defcend- 
ing diredtly from the epiglottis into the cavity of the 
body 
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