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VIII. An EJfay on the Trachea or Windpipes of various Kinds of Birds, 

 By John Latham, M.. D. K R. S. and L. S. Romjey. 



Read- July 4, October 3, and November 7, 1 797. 



THE 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 publiih 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 mofl Ornithologifts have thought it 

 fufficient to difcriminate one fpecies from another, I have alfo paid 

 fome attention to the ftru&ure of the internal parts ; and, among 

 other things, the difference in the formation jof the trachea in many 

 of the Duck genus, in particular, has not failed to ftrike my obferva- 

 tion ; and that this circumflance will not a little contribute to afhft 

 our refearches concerning the identity of feveral fpecies, hitherto 

 not a little confufed, will hereafter be made to appear. But as I 

 wifhed to get as much light thrown on the fubjea as poflible ; I 

 have poftponed the publication of my obfervations, until by repeated 

 difleaions, and comparing many individuals with one another, I 

 might be enabled to fpeak 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 



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