60 MR. A. H. GARROO ON THE GROUND-HORNBIL.L. [Jan. 18, 



January 18, 1876. 

 Robert Hudson, Esq., F.R.S., V.P., in the Chair. 

 The following papers were read : — 



1. On a Peculiarity in the Carotid Arteries, and other Points 

 in the Anatomy, of the Ground- Hornbill [Bucorvus 

 abyssinicus). By A. H. Gakrod, M. A., F.Z.S., Prosector 

 to the Society. 



[Received December 10, 1875.] 



A specimen of Bucorvus abyssinicus having recently died in the 

 Society's Gardens, I have had the opportunity of examining the 

 anatomy of that genus for the first time. In all respects, except the 

 one to be referred to as regards its arterial system and a minor myo- 

 logical feature, it agrees with Buceros. As is the case iu all the 

 Bucerotidse, there was not a trace of fat to be found on any part of 

 the body of the adult bird, though it may be present iu young 

 individuals; and the air-cells extended so extensively among the 

 muscles that on removing the skin no dissection was required to 

 display each muscle from origin to insertion. The muscular tissue 

 was also strikingly compact and dry, as in the Hares among mam- 

 mals, in which animals also it is known that fat is never deposited. 

 The oil-gland, as in Buceros, instead of being simply tufted, was also 

 covered with a dense mat of short feathers, about a square inch in 

 area. 



In Buceros, as in most birds, the two carotid arteries, immediately 

 they separate from their respective innominate arteries, converge, 

 and meet before they have gone any considerable distance up the 

 neck, to run together in the median hypapophysial canal on the 

 anterior surface of the cervical vertebrae. In some Parrots the left 

 carotid, instead of coursing the above-mentioned canal with its 

 fellow, runs up along the side of the neck together with the left 

 pneumogastric nerve to reach the head. Iu Bucorvus, in the specimen 

 dissected by me at least *, a further extension of this peculiarity ob- 

 tains ; for both the carotids, instead of meeting and running toge- 

 ther, course up the sides of the neck in company with the pneumo- 

 gastric nerves and jugular veins of their respective sides, as they do 

 in mammals, and in no other birds, as far as I am aware. Another 

 peculiarity is, that these abnormally placed carotids are particularly 

 small in calibre ; and I noticed that the vertebrals were as conspicu- 

 ously large, evidently to make up the blood-supply of the head. 



As to the visceral anatomy, it may be mentioned that the uni- 

 formly cylindrical crop leads, through the zonary proventriculus, to 

 the stomach, which is much like that of Buceros-\, bnt more mus- 

 cular, and with the dense epithelial lining much more firmly 



* A second specimen, since received, entirely agrees with the above descrip- 

 tion. 



t Vide Trans. Z. S. toI. i. pi. xviii. p. 122. 



