Keywords: PZSL1889Page589.png above Bucorvus abyssinicus Bucorvus abyssinicus <small> Boddaert 1783 </small> below Buceros rhinoceros Buceros rhinoceros <small>Linnaeus 1758</small> en Syrinx of Abyssinian Ground Hornbill above and Rhinoceros Hornbill below from frontal Proceedings of the Zoological Society of London http //archive org/details/proceedingsofgen89zool vol 1889 issue 4 http //archive org/stream/proceedingsofgen89zool page/589/mode/1up page 589 1889 published 1890 F E Beddard text PD-old-70-1923 PZSL 1889-4 Bucerotidae anatomy Bucorvus abyssinicus Buceros rhinoceros Syrinx bird anatomy |