t20 Dr. Latham'j Efay on the Trachea or Windpipes of Birds. 



The trachea here is more confpicuous on account of the bony 

 dilatation in the middle of it than for any other circumftance : in- 

 deed a manifeft difference from any other may be obferved juft below 

 the larynx, being an oblong bony cavity of nearly an inch in length. 

 From this part the trachea defcends for near two-thirds of its length, 

 when it fwells out into a ftrong bony hollow, flat on one fide, and 

 moderately convex on the other, about the fize of a fmali walnut. 

 At the divarication the parts again lofe their rings, and become bony, 

 not greatly enlarged, but equally fo on both fides — the two bron- 

 chi? taking rife at the under part of this laft bony hollow. I have 

 obferved fome diverfity in the trachea of this fpecies, and in one in 

 particular the hollow round bone was lefs oflified j befides which, the 

 oblong bone next the larynx differed much in being ftiorter, (Fio-. 6.) 

 as alfo the bony part at the bifurcation of fcarcely more than half 

 the dimenfions, (Fig. 7.) — which laft circumftances taken together 

 feemed to prove its being a young bird. 



We now clofe the account of fuch fpecies of the Duck Tribe 

 as the males of them have fomewhat in the conformation of the 

 trachea differing from the other fex; and I flatter myfelf, that, 

 by means of the preceding descriptions, aided by engravings of the 

 parts in queftion, the reader will find every thing as clear as was 

 meant to be. 



Endeavouring to add to this lift, I have examined feveral others of 

 the Duck genus, as the Grey Lag, White-fronted, Bean, Bernac/e, 

 Brent and Scoter; in none of which have I ever found any thing 

 remarkable. —But I mean not to defift from the enquiry, and recom- 

 mend attention to it by others ; for I truft that many fingular and 

 curious occurrences will be difclofed on a further inveftigation of the 

 fubjecl. 



WE 



