SCREAMERS. PELICANS. 69 



Order XVIII. PALAMEDEIFORMES. 



Family PALAMEDEID.E. SCREAMERS. 



This Order includes only three species referable to two genera, which, [c age 42.1 

 though most nearly allied to the Ducks, differ from them in many 

 important particulars. The bill is short and fowl-like with a decurved 

 tip, without laminae or tooth-like processes on the sides, and the long 

 toes are only partially united by rudimentary webs. The skeleton 

 shows some very remarkable peculiarities, such as the absence of uncinate 

 processes to the ribs. 



The three known species are all peculiar to South America, and are 

 represented by the Derbian Screamer (Chauna chavaria) (795), a heavy 

 looking bird with the wing strongly armed with a couple of powerful 

 spurs. They frequent marshes and shallow water, wading and swimming, 

 and in spite of their weight are birds of powerful flight, soaring in 

 immense spiral circles till they are almost out of sight. Standing with 

 head thrown back, both male and female utter a very loud cry, which 

 may be heard at a distance of two miles. 



Screamers are often kept by the natives in a state of domesticity, and 

 prove efficient guardians of the poultry-yard against birds of prey and 

 other enemies. 



Order XIX. PELECANIFORMES. PELICANS AND ALLIES. 



The members of this Order, often called Steganopodes, are character- [Cases 

 ised by having the hind toe united to the second toe by a web, so that 43,44.] 

 all four toes are webbed. In this respect they differ from all other 

 birds. They are sociable in their habits, and as a rule feed and nest in 

 companies, their food consisting almost exclusively of fish. 



Family I. PHALACROCORACID.E. DARTERS AND CORMORANTS. 



The four species of Darters or Snake-birds (Plotus) (797-799), two 

 of which are exhibited on the lowest shelf of this Case, are fresh-water 

 divers inhabiting the tropical and warmer temperate regions of the 

 world. They are remarkable looking birds, with the bill long and 

 pointed and the edges of the mandibles serrated to enable the bird to 

 hold its slippery prey. As may be seen by examination of the skeleton 

 (798), the articulation of the cervical vertebrae is very remarkable and 

 the curious " kink " in the neck, so characteristic of these birds, is really 

 a spring-like arrangement worked by powerful muscles. When the 

 bird spears a fish the " spring" is released and the bill darts forward 



