1843.] Mr. Blyttis Report for December Meeting, 1842. 993 



specimens, that these ridges are thus pushed forward till they finally 

 scate off anteriorly, while others are continually in process of formation 

 behind ; also that in young birds they are individually much larger and 

 thinner in substance, becoming narrower and closer by degrees. I re- 

 member making an analogous observation in the instance of the very 

 remarkable long-legged Abyssinian Hornbill (or Abba Gumba of Bruce, 

 sub-genus Bucorvus of Lesson), the casque of which forms a hollow tube, 

 open in front in the adult, and which continually advances forward, the 

 extremity shredding off, from time to time, in form of a ring. We 

 have seen that the transversely grooved plating on the sides of the base 

 of the upper mandible of B. Nipalensis, and necessarily of cassidix 

 and what other species possess an analogous structure, is constantly 

 renewed behind and worn away in front in like manner. 



I now return to the ordinary Hornbills without a gular bag, and of 

 which the sexes are similar in plumage, as exemplified by B. cavatus, 

 rhinoceros, Malabaricus, &c. It is among these that the casque 

 attains its maximum dimensions, being generally not large in the 

 preceding group. I have already remarked that Levaillant's figure of 

 B. rhinoceros, which is copied by Shaw, represents the tail to be 

 black with a white tip, and the rest of the plumage to be wholly 

 black ; whereas the considerable number of specimens which have 

 passed under my observation have invariably had the thighs, vent, 

 and lower tail-coverts, white, and the tail white with a black cross- 

 band as in B. cavatus : a circumstance which tends exceedingly to 

 diminish our faith in the alleged colouring of B. cavatus, as distinct 

 from the Indian Homrai. Sir Stamford Raffles rightly remarks that 

 the female of B. rhinoceros is smaller, with the horn more recurved ; 

 and that the iris is white, while that of the male is red : this corres- 

 ponds with Mr. Hodgson's observation of the diversity of colour of the 

 irides in the sexes of B. cavatus, and which probably obtains likewise 

 in Malabaricus and some others. 



The two next have been much confounded, for which reason I shall 

 describe them fully. 



3. B. Malabaricus (verus), Latham ; B. monoceros, Shaw, and 

 probably also B. violaceus, Shaw : Bozgrna Dunnase of Lieut. White, 

 As. Res. IV, 119. Black with white under-parts from the breast, also 

 the tips of the primaries and secondaries, and the entire three outer 



