BYCANISTES SUBQUADRATUS 



BLACK-AND-WHITE-CASQUE HOKNBILL. 



Bycanistes subquadratus, Cabanis, Journ. fiir Ornith. (1881) p. 350, pi. i. 



Hab. Angola. 



This Hornbill was described by Professor Cabanis, in the ' Journal fiir Ornithologie ' as above 

 quoted, from a specimen procured by Herr Otto Schiitt. It resembles in its colour and markings 

 the species described as Buceros subcylindricus by Dr. Sclater, from a specimen living in the 

 Zoological Gardens, Regent's Park, and is apparently the adult male of that form. Sclater's bird 

 was immature ; and at the time his description was published the casque was small and sloped 

 forwards to the culmen ; but after some time had elapsed it had grown considerably, and nearly 

 covered the entire length of the maxilla. This difference in the casque is shown by a comparison 

 of the plate published in the 'Proceedings of the Zoological Society' for 1870, pi. 39, with the 

 one published in this work. The sex of B. subcylindricus is not known ; but it may be a female, 

 which might account for the casque being smaller than that of Cabanis's bird, a figure of which 

 is given in the opposite Plate. This casque presents the chief characters for separating the two 

 birds as distinct species. In B. subquadratus it is high, commencing in the feathers of the crest 

 above the head, and extends forwards in a gradual curve over two thirds the length of the 

 maxilla, where it terminates with the anterior edge at a right angle to the culmen. The casque 

 is black, with a white patch covering two thirds of the upper portion, with a projection in the 

 form of a U extending downwards on the side a little over halfway to the culmen. This mark 

 may be characteristic of the species, or it may be a peculiarity of certain individuals, as is seen 

 in some specimens of Anorrhinus galeritus, and may possibly indicate age. I have noticed this 

 yellowish-white marking upon the bills of A. galeritus ; but as it occurred on specimens obtained 

 in the same localities with others having all black bills, I never deemed it of any specific value. 

 It certainly is a very peculiar mark in the bird described by Herr Cabanis (which bears every 

 indication of being an old male), and may be in this instance a specific character ; but it would 

 be desirable to have more examples for examination before regarding B. subquadratus as distinct 

 from B. subcylindricus. At present we can only represent the two birds under the names their 

 describers gave them, trusting for additional information in the future to decide the question of 

 whether they are distinct or not. Of course, should they prove to belong to the same species, 

 the name subquadratus will become a synonym of that bestowed by Sclater on his species. 



Casque as described above. Bill black, with a narrow band at the base yellowish. A long 

 greenish-black crest covers the top and back of the head. Sides of the head greenish black, each 

 feather edged with ash-grey. Ear-coverts light ash-grey. Mantle, wings, and breast metallic 





. 



