158 LECTURE V. 



lengthened feathers, constituting what is called 

 the false or spurious wing; the alula or alulet 

 of some ornithologists. The tail, in most birds, 

 consists of twelve feathers ; in some of ten only ; 

 iand in some others of eighteen, twenty, or twenty- 

 four. Sorrietimes on each side the tail or above 

 it, at the lower part of the back, are placed se- 

 veral very long feathers of a different structure 

 from the rest: these have been called the hypo- 

 chondriac and unpygial feathers. These are the 

 principal distributions of the feathers on a bird. 

 With respect to the particular shape of the fea- 

 thers themselves, they vary greatly in tli:e different 

 tribes. 



The particulars most important In the com- 

 parative anatomy of birds are these. The throat, 

 after passing down to a certain distance, dilates 

 itself into a large membranaceous bag, answering 

 to the stomach in (juadrupeds : it is called the 

 crop, and its great use is to soften the food taken 

 into it, in order to prepare it for passing into 

 another stronger receptacle called the gizzard: 

 this which may be considered as a more powerful 

 stomach than the former consists of two \ery 

 strong muscles, lined and covered with a stout 



