FWI 



XX11 



INTRODUCTION. 





The Btjcerotid^e appear to me susceptible of arrangement into two divisions or subfamilies, 

 containing the Ground- and TREE-Hornbills respectively. Of the first of these we have at the 

 present day three species, which possibly are the sole remaining members of what may have been 

 an extensive group, and differ from the rest of the family in many particulars, the most 

 conspicuous of which are the long legs formed for walking, whereas all the other species have short 

 legs and can only hop. Myologically, also, these birds differ from the rest of the Btjcerotid^: in 

 having only two muscles of the thigh represented, viz. the semitendinosus and the accessory 

 semitendinosus; while the ambiens, the femoro-caudal, and the accessory femoro-caudal are 

 absent. In the genera Buceros and Tockus the accessory femoro-caudal muscle is present. 

 Eor this subfamily I would propose the term Bucorviisme. The other, Bucerotin.^, contains 

 the remaining species, amounting to over fifty in number, comprising various groups allied to 

 each other in the form of their casque and general colour of plumage ; and in many of them their 

 natural affinities are further upheld by their geographical distribution. The genera for these 

 various forms have been many, all authors seeming to appreciate the difficulty of retaining these 

 birds in one or two genera, as the older writers did. Of the thirty-four genera proposed, I have 

 employed nineteen, which, I consider, fairly represent the different forms existing at the 

 present day. The single genus Tockus is made to contain perhaps some species which might be 

 deemed at least subgenerically different from the typical style ; but I do not think it essential to 

 make any such divisions, as in the main the species are all really members of one genus, the 

 more or less slight elevation of the culmen being about the only character which could be 

 urged in behalf of a separation of the species. 



I commence the arrangement of the family with the genus Bucorvus, containing three 

 species. These birds have many characteristics to separate them from the other members of 

 Bucerotim. They are essentially ground-birds, yet ascend to the branches of trees ; but their 

 home is the ground, over which they walk with ease, while their relatives are tree-loving birds, 

 descending but rarely to the earth, upon which they move by awkward hops. Here at once is 

 perceived a great difference of habit ; and to accommodate the Ground-Hornbills to their different 

 life, their anatomical structure is modified. The second subfamily, Bucerotijoe, contains the 

 greater part of the family ; and these all live in and among the trees. I begin with the genus 

 Buceros as containing a typical form of the true Hornbill, with two species, the chief (and perhaps 

 only) difference between them being the upturned casque of the one, and the straight casque of the 

 other. The third genus, Dichoceros, was formed for the well-known bicomis, the anterior corner 

 of whose horns turns slightly upward. Next to this, as belonging to the flat-casque group, 

 I place the genus Hydrocorax, with three species ; to be followed by Bhinoplax, containing 

 the extraordinary bird with solid casque, bare neck, and elongated median rectrices. Between 

 all these genera gaps exist, which at the present time we are unable to fill ; but we may feel 

 assured that the extinct species which once supplied the desiderata were no less wonderful in 

 structure than are their relatives which remain with us. Anthracoceros now introduces the 

 species bearing an upright, more or less lengthened, laterally compressed casque. It contains 

 fLYe species, possessing, for the size of the birds, quite large casques, highest anteriorly. Pour 



