BUCEROTtDiE BUCORAX 101 



eleven primaries, ten tail-feathers ; the under wing-coverts do not 

 cover the basal portion of the quills below and perhaps this may 

 account for the loud noise made by these birds when flying, the 

 sound being produced by the rushing of air between the quills ; the 

 oil gland is tufted, and further covered by a dense mat of short 

 feathers ; spinal feather tract not defined by lateral bare tracts on 

 the neck ; caeca absent. 



The sexes are alike in plumage though the colours of the soft 

 parts and the bills show sometimes sexual distinctions ; the eggs 

 are white and the young are born helpless. 



The family is found all over the Ethiopian and Oriental regions, 

 extending eastwards through the Malayan Isles to New Guinea and 

 the Solomons. 



Key of the Genera. 



A. Tarsus long, twice the length of the middle toe and 



claw Bucorax, p. 101. 



B. Tarsus about equal to, or less than the length of the 



middle toe and claw. 



a. Bill without, or with only a small, keel-shaped 



casque Lophoceros, p. 108. 



b. Bill with (in the South African species) a large sub- 



cylindrical casque extending behind the eye. ...Bycanistes, p. 106. 



Genus I. BUCORAX. 



Type. 



Bucorvus, Less. Train Orn. p. 259 (1831) B. abyssinicus. 



Bucorax, Sundev. 0/vers. K. Vet. Akad. Handl. vi, p. 



161 (1849) B. abyssinicus. 



Bill long, pointed, compressed and slightly curved ; casque 

 covering the basal third or more of the culmen, either elevated and 

 open in front or keel shaped and compressed ; no crest ; throat 

 naked and wattled; tail short, the feathers sub-equal, about half 

 the length of the wing ; tarsus long, about twice the length of 

 the middle toe and claw. 



This genus is further distinguishable from the others of the 

 family by several anatomical characters of some importance ; the 

 chief of these is the arrangement of the arteries of the neck ; the 

 usual carotids carrying the blood to the head, which in other genera 

 of the family join together at the ottom of the neck and run along 

 the hypophysial canal formed by the ventral processes of the 



