408 NATURAL HISTORY OF BIRDS. 



tlie male bring anything but forjd ; and I never fouml any food which had bcfii 

 rejected under the tree, and but very little ordure, which hitter liad aj>j)arentiy been 

 tlirown out l)y tlie foniale wiien the closing-work was finished. The male bird would 

 alight near, tijeii lly to the hole, holding on to the bark by iiis claws, and knock with 

 his beak. On tliis the points of that of the female aj)peared, and received the fruit, 

 when the male flew off. The hole was at first, j)erha])s, six inches in height, and three 

 or four wide. When closed up, the opening at the widest part was a little larger than 

 would admit the finger. It siiould, however, be borne in mind that the bill opened 

 u])wards, and thus had three or four inches j)lay. Tiie ]>lastering operation took two 

 or three days, after which the ordure was tlinnvii out." 



We might continue with similar testimony from Wallace, Bernstein, and other 

 travelers, but want of space prevents us from quoting more, inasmuch as ihc ai)ove 

 will suffice to give an idea of one of the most extraordinary nesting habits we know 

 of. Wo do not wonder that the hornbills play a great role in the imagination of the 

 natives, and find it quite natural that the female hornbill is regarded by the Burmese 

 as a model of virtue. 



The hornbills vary in size from that of a raven to that of a jay ; and there is an 

 endless variation of the casque from u nearly obsolete ridge to the immense upturned 

 horn of the rhinoceros bird. A somewhat more aberrant form is Ji/iinoplax vigil, 

 which has a solid, not cellular, casque, bare neck, and elongated central tail-feathers. 

 It lives in the Malay i)eninsula, Sumatra, and Borneo. 



There seems to be good reasons for regarding the ground-hornbills, three African 

 species, one of which is illustrated in our cut, as constituting a special sulj-family. 

 Their casque is hollow, and open in front in the species figured ; the tarsi are long 

 and the tail comparatively short. There are also important internal differences from 

 the other hornbills, for, while these have a muscular formula of AXY, the ground 

 hornbills have only XY. The difference in the e.\ternal structure of the feet and in 

 the myological formula is concomitant with a peculiarity in the movements of these 

 birds, as the tree-hornbills hop with both feet together, while the ground-hornbills 

 (Bucorvinte) walk, placing one foot in front of the other. A unique anatomical 

 feature has been described by Mr. W. Ottley. Some of the tree-horiil)ills have two 

 caroti<ls, others have one; but Bucorru^ has no functional carotid at all. The 

 vessels are only represented l)V two imi)erforate fibrous chords, and their function 

 is performed by the greatly enlarged rejiresentatives of the comes nervi i'a;/i. 

 Hence, the origin of the arteries for the siii>ply of the head also differs from the 

 usual arrangement, a superior thyroid artei-y and a facial artery being both absent. 

 As might be expeded, the habits of the ground-hornbills are difTerent from those 

 of their tree-loving relatives. They move with ease over the ground, on which they 

 S])end much of their time, feeding upon insects, reptiles, and occasionally small 

 mammals. 



Few birds can better illustrate the necessity of taking into account all the char- 

 acters in determining the jilaee in the .system than those composing the present super- 

 family, the UPUPOIDEx'E. If we only knew their skin, the posterior part of their 

 breastbone, their deep plantar tendons and carotids, we should most certainly refer the 

 hoopoes to the Passeres ; but since, al.so, all the other points of their extern:il and 

 internal anatomy are well known, there is no room for doubt but that the)' form an 

 isolated group belonging to the Picarian order, the nearest allies being probably the 

 hornbills, as already mentioned. Still, as they are yet classed with the larks or with 



