XVI INTRODUCTION. 



many wide gaps to be filled up before our information on tbis subject 

 can be considered in any degree complete. Still less perfect is our 

 knowledge on many otber points connected with the history of this 

 genus of birds. We are at present utterly ignorant of all that regards 

 their propagation, nidification and internal structure, and in reality we 

 know merely such facts concerning them as can be deduced from the 

 examination of their dried skins. I cannot conclude this prefatory 

 statement better than by calling attention to these deficiencies in our 

 knowledge, and by remitiding those, who have opportunities of ob- 

 serving these and other animals in their native wilds, how much it 

 is in their power, by observations on these and similar points, to in- 

 crease our knowledge of the wonderful and varied productions of 

 Nature. 



