INTRODUCTION. 



xix 



of them families specially characteristic of the Patagonian Avifauna, and 

 both of them are represented in the Argentine Republic. One other 

 Passerine form is also worthy of special mention. The Dippers (Cin- 

 clidse) are essentially an Arctic group diffused all over the Palaearctic 

 and the Arctic Regions. It is singular, however, that this form should 

 reoccur at higher elevations in the Neotropical Region. A Cinclus is 

 found in the mountains of Colombia, another in the Andes of Peru, and 

 a third has lately been discovered in the northern sierras of the Argen- 

 tine Republic. As regards Passerine birds, therefore, which great order 

 makes up more than one half of the Argentine Ornis, we may say that 



