SCREAMERS.—PELICANS. 69 
Order XVITT. PALAMEDEIFORMES. 
Family PataMeprip#®. ScrReEAMERS. 
This Order includes only three species referable to two genera, which, 
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 lamine 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) (195), 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. PeEtuicans AND ALLIES. 
The members of this Order, often called Steganopodes, are character- 
ised by having the hind toe united to the second toe by a web, so that 
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. PHatacrocoracip&. DartEeRs AND CoRMOoRANTS. 
The four species of Darters or Snake-birds (Plotus) (191-199), 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 vertebree 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 
[Case 42. | 
[Cases 
43, 44.] 
