INTRODUCTION. 



The Bucerotidae, or Hornbills, on account of the large size of many of the species, together 

 with their apparently unwieldy and curiously formed casques, are very conspicuous among the 

 families which constitute the class Aves. Their habits are no less uncommon than is their 

 aspect ; and the unique one possessed by the males of enclosing the female in the hollow of some 

 tree, firmly fastening her in by a wall of mud, and keeping her a close prisoner until the eggs 

 are hatched, is not paralleled by the customs of any other species of birds known to naturalists. 

 Another curious habit is that of casting up the entire epithelial lining of the gizzard in the 

 form of a sac or pocket, filled with undigested particles of food or hardened objects that may 

 have been swallowed. Owls, as is well known, eject little round pellets, composed of the fur 

 and bones of the small mammals upon which they have fed ; but these are not accompanied, as a 

 rule, by any portion of the bird's internal structure. The Hornbills, however, apparently suffer 

 no inconvenience from the deprivation of their gizzard's walls ; and an individual has been 

 observed to quietly investigate with the point of his bill the contents of one of these sacs, 

 which he had just cast forth, and which he would have probably swallowed again had not the 

 bag been removed. In the present Monograph I have endeavoured — first, to review the 

 literature of the Family from the time of Linnaeus to the present day ; secondly, to recapitulate 

 the various genera which from time to time have been proposed for the different species ; thirdly, 

 to discuss the classification and geographical distribution of the various distinct forms ; and, 

 fourthly, to give the synonymy and life-history of each one, so far as these are known to me. 

 In the arrangement that I have thus proposed, the first subject that presents itself is the 

 Bibliography of the Family, of which I commence the review with the twelfth edition of 

 Linnaeus's ' Systema Naturae,' published in 1766. 



1766. Linn^us, Systema Naturae. 



In this edition the great systematist has recorded the species of this family known to him, 

 retaining them all in the genus Buceros. Four only are mentioned, viz. B. BICOUNIS, 

 B. HYDBOCOBAX (=PLANICOENIS, Merrem, HYDEOCOEAX having been established 

 as a genus by Brisson), B. BHINOCEEOS, and B. NASUTUS. All these are recognized at 

 the present day. Species 4. 



