Vv OTIDIDAE 261 
is Y-shaped, and often ancylosed with the sternum, the syrinx is 
tracheo-bronchial. An after-shaft is present, and the down, which 
is uniform in the young only, is in them mottled with black and 
lighter tints. A most remarkable phenomenon, moreover, is 
the gular pouch, opening under the tongue, found in the male of 
some examples of Otis tarda during the breeding season. This 
pouch becomes very small or vanishes altogether at other times of 
Fic. 54.—Great Bustard. Otis tarda. x4 or 75. 
the year, and seems to be restricted to adult birds. Similar, 
but smaller, processes have been observed in Hupodotis kori, 
E. edwardsi and, it is said, Otis tetrax; while dilatations of the 
oesophagus have been recorded in £. australis and Neotis denhamt. 
Otis tarda, the Great Bustard, which, as a native, only became 
extinct in Norfolk about 1838, used to extend from East Lothian 
to Dorset, but is now merely an occasional visitor to Britain. 
The upper parts are mottled with rufous, buff, and blackish- 
