[ 365 ] 



XXIV. Remarks on Aquila desmursii. 

 By J. H. GuRNEY, M.P., F.Z.S. 



Read May 27, 1862. 



[Plate LXXVIL] 



JM. Jules Verreaux, who first recognized this Eagle as distinct from its congeners, 

 communicated his description of it to Dr. Hartlaub, by whom the species was made 

 known to ornithologists in his admirable work on the ' Ornithology of West Africa.' 



My present object is to put on record some information as to this interesting bird, 

 with which M. Jules Verreaux has been so good as to supply me, and also to give some 

 indications of the changes of plumage to which this species appears liable, and which I 

 have had the opportunity of examining in several examples which now form part of 

 the collection of the Norwich Museum. 



It may, however, be well to premise a few general remarks with reference to the 

 geographical distribution of this Eagle, and to some of the peculiarities by which it is 

 distinguished. 



Aquila desmursii has hitherto only been found in Tropical Africa, north of the Equator, 

 — specimens having been obtained at Bissao on the western coast, and also in Nubia 

 and Abyssinia, and on the banks of the White Nile. 



It is a small species, intermediate in size between Aquila pennata and Aquila ncsvia. 

 From the former it is readily distinguishable by the greater length of all its measure- 

 ments ; from the latter (as also from Aquila ncBvioides) it may, on the contrary, be di- 

 stinguished by its less size and, as Dr. Hartlaub well remarks, " by the mote deli- 

 cately shaped bill, and by the greater length of the tail " as compared with that of the 

 wings. 



Another well-marked distinction to which Dr. Hartlaub does not allude is to be found 

 in the presence in Aquila desmursii of a well-defined, though small, occipital crest, con- 

 sisting of from eight to nine pointed feathers, the longest of which are fully an inch 

 and a half in length. 



The colouring of this Eagle, described in Dr. Hartlaub's work, is that which charac- 

 terizes what I believe to be the adult bird after it has newly moulted and has acquired its 

 fresh plumage. In this dress the general coiowv'm^oi Aquila desmursii closely resembles 

 that of the adult o{ Aquila ncevioides under similar conditions, being of a rufous brown, 

 varying in intensity in different portions of the same feather. 



Other specimens of Aquila desmursii exhibit a plumage of an extremely dark and 

 almost uniform chocolate-colour. These individuals I believe to be immature birds, in 



