AERATION OF CHAUNA 



placed the birds known as Screamers or Kamichis, 

 known to us by three species, usually referred to two 

 distinct genera, viz. Chauna and Palamedea. The 

 Derbian or the crested screamer (Chauna derbiana and 

 C. cristata) is a bird which looks like nothing else in the 

 bird way. It has the head of a fowl attached to the body 

 of a good-sized goose, the whole surmounted upon 

 longish legs with straddling toes. The long legs suggest 

 wading, and the large " feet " with divaricated toes safe 

 progression upon treacherous and marshy soil. The 

 bird is in fact at least partly aquatic ; and the likeness 

 to a goose is not wholly a matter of outward appear- 

 ance. But it cannot be definitely placed in that large 

 order, which includes the geese, swans and ducks ; 

 rather is it to be looked upon as the vestige of a group 

 which perhaps produced, as a mere side issue, the anati- 

 form birds. The main stem with its archaic characters 

 has come down to us in these three desolate birds which 

 form the subject of the present article. 



The chaunas have a puffed out and even gouty appear- 

 ance about the legs. Coupled with a slowish gait this 

 suggests overfeeding, a complaint which is not un- 

 known at the Zoo through the unnecessary kindness of 

 visitors. It is, however, merely a conspicuous expres- 

 sion of a state of affairs which characterizes birds in 

 general and not the screamers only. These birds, 

 like others, are literally " puffed out with wind and the 

 rank mist they draw " in order to lighten their some- 

 times cumbrous bodies. The lungs of birds are not 

 simply bags more or less subdivided into multitudin- 

 ous chambers as in ourselves and other animals ; but 

 they communicate with a complex system of ramifying 

 air cavities spread through the body and permeating 

 even their very bones. There is hardly a portion of the 

 bird's body which is free from air- containing spaces, a 

 state of affairs which obviously aids it in spurning the 



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