554^ CLASS AVES. , 



In young individuals, scattered feathers are sometimes ob- 

 served of a colour different from those in the midst of which 

 they are found ; such feathers belong to the next succeeding 

 coat, which have appeared sooner than their usual time, and 

 indicate the colour which shall be proper to the peculiar parts 

 on which they are found. These feathers constitute an excel- 

 lent criterion, by which to refer these young birds to their pe- 

 culiar species. 



When the plumage of the female does not differ from that 

 of the male, it is yet observable that the tints are less pure and 

 less lively ; there is also, at times, a variation in the colour of 

 the bill. 



The following peculiarities are worthy of remark in the in- 

 ternal structure of the parrots. The head is strong, and the 

 cranium rounded ; the os furcatum is a little pointed towards 

 the sternum, and formed like a V. The sternum is furnished 

 with a|)owerful keel, or median crest ; there is neither lateral nor 

 posterior emargination ; its body, on the contrary, is very wide, 

 and only provided with an oval foramen, moderately large, and 

 closed by a membrane near the abdomen, similar to that in the 

 birds of prey, and palmipedes. The lower lar3nix is compli- 

 cated, and provided with three peculiar muscles ; a circum- 

 stance which, united to the mobility and conformation of the 

 tongue, may produce the facility with whicli these birds imi- 

 tate the human voice. Their gizzard resembles that of fru- 

 givorous and granivorous birds ; their intestines are very long, 

 and destitute of coecum ; the liver is of middling size, and 

 divided into two lobes, nearly equal. The spleen is small and 

 round. The heart is of moderate size, and rounded at the 

 end. 



The usual habitat of these birds is under the torrid zone, 

 both in the old and new continent, and in the Oceanic islands. 

 The greater number of species are found under those parallels 

 which are nearest the equator ; but some are extended in both 

 hemispheres, to very high latitudes. Thus, in the northern 



