2126 FLAMINGOES, DUCKS, AND SCREAMERS 



tivity, 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 in- 

 terior, where you find them in smaller streams, they are rarely in parties of more 

 than three or four most generally at that time in pairs 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 rapid." Although gen- 

 erally silent, mergansers utter at times, especially when on 'the wing, a harsh, un- 

 musical kurr. Three beautifully -colored birds from the mountains of Chili, Peru, 

 and Ecuador, constitute the allied genus Merganetta. 



THE SCREAMERS 

 Order PALAMEDE^ Family PALAMEDEID& 



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

 on p. 1464, 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 specialized group, although in some other ways they are gen- 

 eralized. Although these strange birds exhibit certain resemblances in their inter- 

 nal 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 scream- 

 ers 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 characterized 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 

 backward. 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 color 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 

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

 and third toes are free, the third and fourth are connected at the base by a web. 

 The long and powerful wings have the third quill the longest, the rounded tail 



