Dr. L a th A M 'j EJfay on the Trachea or Windpipes of Birds. 9 7 



found : and further, that it is the wale alone which has this mark 

 of difcrimination ; for although many birds may be found having 

 the female plumage, in which the labyrinth is equally confpicuous 

 with others poiTefiing that of the other fex, yet I will venture to 

 affirm, that this part differs not from that of an old male, except in 

 refpedf. to the offification being Jefs complete; and again, that in 

 every fpecimen with fuch enlargement of trachea, or labyrinth, 

 the teftes, an indubitable mark of the male fex, will invariably be 

 found to accompany it. 



Among other errors, the Glaucium of authors, or Morillon of the 

 French, has been recorded as a diftincl fpecies by many. This how- 

 ever may eafily be proved a fallacy by diiTedtion, as the bird is no 

 other than the Golden Eye in imperfect feather ; for this fpecies does 

 not attain the adult plumage for at lead the firft feafon, perhaps 

 longer. Another bird, palling under the name of Morillon, proves, 

 by the fame teft, to be the young of the Tufted Duck ; and a third 

 called Morillon alfo, merely a young Scaup, which I have more than 

 once identified. Befides, were the difference of bill alone in thefe 

 birds attended to, it could not fail to decide the matter, as they are 

 greatly unlike each other in this particular, notvvith (landing the 

 external colour of feather might lead a fuperficiai obferver to think 

 them the fame. 



The wild Swan is not greatly unlike the tame fpecies in refpect to plu- 

 mage, the difference of bill at firft fight appearing to be the chief ex- 

 ternal charafteriftic, infomuch as to deceive fome Naturalifts into the 

 fuppofition of their being varieties only of one and the fame fpecies*; 



but 



* M. de Buffon was apprifed of the difference of internal ftrutture, but accounts for it 



on a fingular principle, when he obferves in a note : " Selon Willughby cette particularise 



*< de conformation eft propre au cygne fauvage, & ne fe trouve point la meme dans le cygne 



" domeftique, ce que femble fonder ce que nous allons rapporter de la difference de Ieur 



Vol. IV. O " rolx, 



