[8650 J 
XXIV. Remarks on Aquila desmursii. 
By J. H. Gurney, M.P., F.Z.S. 
Read May 27, 1862, 
[Pirate LXXVIL.] 
M. Juxes VerreAvx, 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 desmursu 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 nevia. 
From the former it is readily distinguishable by the greater length of all its measure- 
ments ; from the latter (as also from Aquila nevioides) it may, on the contrary, be di- 
stinguished by its less size and, as Dr. Hartlaub well remarks, ‘‘ by the more 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 colouring of Aquila desmursi closely resembles 
that of the adult of Aquila nevioides 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 
