Hornbill Embryos and Nestlings. 547 



shoulders, and though its extent is considerably greater 

 in the nestling of Anthracoceros malayanus (Stage 5), it is 

 there correlated with an almost entirely naked neck, an 

 arrangement which I am inclined to think primitive. The 

 long ajjt. coll. ventr. of the Upupidse is represented by a 

 short expanse above the junction of neck and body in the 

 young of A. malayanus ; but the branching of the ventral 

 pteryla in the Upupidoe is in all Hornbills quite unparalleled ; 

 for, as shown on p. 543 and p. 546, the branch of the ventral 

 tract which outwardly bounds the ajH. pectorale arises from 

 a point low down on the tract to run upward, while in the 

 Upupidse it arises at the upper extremity to run downward. 

 The junction of the pt. humeralis and jo/. femoralis with the 

 dorsal tract is also quite opposed to the arrangement in the 

 Upupidse. 



The Nesting-habits, ^c, o/Buceros rhinoceros. 

 By C. Hose. 



The nest is always built in the hollow of a large tree — the 

 hollow, be it noted, being always due to disease of the tree 

 or to the ravages of termites, not to the personal labours of 

 the birds. The bottom of this cavity is often plugged by a 

 termite-nest and accumulation of decayed wood, and on the 

 upper surface of this is made the nest, a very rough-and- 

 ready structure, composed simply of the feathers of the 

 female. The hollow of the tree communicates with the 

 exterior air by means of a long aperture, which, just before 

 the period of incubation, is closed up almost entirely by the 

 male, simply leaving a long open slit, up and down which 

 the beak of the enclosed female can move. The substance 

 used in thus closing the aperture closely resembles some 

 vegetable resin, and is probably composed of a gastric 

 secretion combined with the woody fragments of fruit. It 

 should be noted that this slit is always in close proximity to 

 the nest, so that the female can easily protrude her beak 

 for food without moving from her sitting position. During 

 incubation the male bird supplies the female with food in 

 the form of pellets of fruit, seeds, insects, portions of reptiles. 



