( 9° ) 
VIII. An Effay on the Trachee or Windpipes of various Kinds of Birds. 
By Fobn Latham, M.D. F.R.S. and L. S. Romfey. 
Read Fuly 4, October 3, and November 7, 1797- 
WHE ftudy of Birds has for many years paft occupied my atten- 
tion ; and I might add, that from my earlieft remembrance I 
have had a predilection in favour of this part of Natural Hiftory, 
although my refearches have not been totally confined thereto. I _ 
have hereby been tempted to publifh my volumes of Ornithology, 
which, I flatter myfelf, are now generally known to the world. 
During my progrefs in the defcription of the external appearance 
of each, the criterion whereby moft Ornithologifts have thought it 
fufficient to difcriminate one {pecies from another, I have alfo paid 
fome attention to the ftructure of the internal parts; and, among 
other things, the difference in the formation of the srachea in many 
of the Duck genus, in particular, has not failed to ftrike my obferva- 
tion ; and that this circumftance will not a little contribute to affift 
our refearches concerning the identity of feveral {pecies, hitherto 
not a little confufed, will hereafter be made to appear. But as I 
wifhed to get as much light thrown on the fubje& as poffible ; I 
have poftponed the publication of my obfervations, until by repeated 
diffections, and comparing many individuals with one another, I 
might be enabled to {peak with the greater certainty. This matter 
has alfo required a much greater length of time in refpect to the 
Duck genus, whofe hiftory will in this effay take up a material part 
of 
