FAM. BUCEROTIDE 
BY Dr. ALPHONSE DUBOIS 

What is especially surprising, is the great lightness of their skeleton; nearly all the 
bones are formed by pneumatic cells. In a great many of these birds, if not in all, the air can 
come as far as the skin, which adheres only weakly on the muscles, and the subcutaneous 
tissue contains some great pouches filled with air. 
Characters. Bill large, stout, slightly curved, and more or less compressed; base of the 
culmen with a variously shaped casque, in some species of large size, while in others it is 
rudimentary or wanting; this casque is generally closed, hollow, and supported by bony tissue. 
Wings ample, covering more or less the base of the tail; under wing-coverts do not cover the 
basal parts of the quills. Tail more or less long and formed by ten feathers. Tarsus strong, 
short, shorter or about equal to the middle toe and claw (Bucerotinae), rarely long (Bucoracinae) ; 
middle toe united at base to the outward toe. 
Margins of the eyelids furnished with strong lashes. Skeleton pneumatic. Palate desmo- 
gnathous. Basipterygoide process absent. 
Eggs white. Young hatched naked and helpless. 
Habits and Reproduction. The Hornbills frequent the tropical forest-lands and all 
except the Bucorvus, live essentially on the trees. Although they live in couples as a rule, they 
are sociable and frequently assemble in great or small numbers. Nearly all walk clumsily, but 
