36o FLAMINGOES, DUCKS, AND SCREAMERS. 



as deep as a cormorant, while when pursued nothing more than the head and neck 

 appears. On the larger Indian rivers, writes Mr. Hume, " they will float down 

 with the stream for a couple of miles, and if not hungry, they rise and fly back 

 again ; but more commonly they fish their way back, diving incessantly the whole 

 way, and, despite their activity, taking a long time to make their way back from 

 where they started from. When gorged, they often sit on some rock in the middle of 

 the water, sitting very upright and cormorant-like, often half opening their wings to 

 the sun. In the interior, where you find them in smaller streams, they are rarely 

 in parties of more than three or four — most generally at that time in pail's — and 

 then they are either flying up-stream or floating down, twisting round and round 

 in the rapids, or fishing vigorously in some deep pool near the foot of a waterfall 

 or I'apid." Although generally silent, mergansers utter at times, especially when 

 on the wing, a harsh, unmusical kurr. Three beautifully coloured birds from the 

 mountains of Chili, Peru, and Ecuador, constitute the allied genus Merganetta. 



The Screamers. 

 Order Palamede^e. Familj^ Palamedeid^. 



If we examine the skeleton of any ordinarj^ bird, such as the one represented 

 on p. 292 of the preceding volume, it will be noticed that some of the anterior ribs 

 are provided with backwardly- directed projections, known as uncinate processes. 

 If, however, we observe that of one of the peculiar South American birds designated 

 screamers, we shall not fail to be struck with the absence of these processes, and as 

 they are present in all other birds and many reptiles, it will be evident that the 

 screamers are a very specialised group, although in some other ways they are 

 generalised. Although these strange birds exhibit certain resemblances in their 

 internal anatomy to the storks and cranes, it is now generally considered that their 

 nearest affinities are with the ducks and flamingoes. Agreeing with those two 

 groups in the features mentioned at the commencement of the chapter, the screamers 

 are readily distinguished from both by their short hen-like beaks, and medium- 

 .sized legs, of which the toes are not completely webbed, but furnished with long 

 claws, the claw of the first toe being specially elongated. Internally, in addition to 

 the absence of uncinate processes, they are characterised by the presence of distinct 

 basipterygoid processes on the rostrum of the skull, by the number of vertebrae in 

 the neck being more than eighteen (which is not the case in the two allied orders), 

 and likewise by the absence of any bare spinal tract in the plumage of the upper- 

 parts ; while the angle of the lower jaw, although recurved, is not much produced 

 backwards. Another peculiarity is to be found in the circumstance that the skin 

 when touched is yielding and crackling, owing to the presence of a layer of air- 

 cells, which communicates to it a bubbly appearance. In colour and texture their 

 eggs resemble those of the geese. 



The screamers are birds of the size of a swan, but of totally different appear- 

 ance, having a hen-like beak, with a waxy growth at the base, medium-sized neck, 

 very inflated crop, a pair of powerful spurs on the front of each wing, and the long- 

 toed legs bare to a considerable distance above the ankle-joint. Although the 



