Mr. R. B. Sharpe’s Catalogue of Accipitres. 421 
between the females of N. spilogaster and the males of N. 
fasciatus, in size as well as in general coloration. 
There is, however, a variation in the markings of the under 
surface in specimens of N. spilogaster, to which I am desirous 
of briefly alluding. Two distinct phases of such markings 
occur in adult specimens, or at least in specimens which 
are so far adult as to have passed beyond the stage of plumage 
which characterizes this Eagle in its first year; and one of 
these phases is much more analogous to the character of 
the lower portions of the plumage in N. fasciatus than the 
other. Thus, in some individuals the white of the underparts 
is merely interspersed with sparse and narrow dark shaft- 
marks, slightly more conspicuous than the corresponding 
markings in N. fasciatus, but otherwise of a similar cha¬ 
racter, whilst in other specimens the dark markings on the 
under surface are much more numerous and also very much 
broader. 
Whether this difference is due to sex or to disparity of age 
I am unable to say : the Norwich Museum possesses two 
nearly adult females of the former type from the Zambesi, 
and two adult males of the latter, one from the Zambesi and 
the other from Natal; on the other hand, the specimen 
figured on pi. 1 of Muller’s £ Oiseaux d’Afrique,’ which is there 
stated to be a male, is represented in the less conspicuously 
variegated plumage, resembling that of the two females pre¬ 
served at Norwich. 
As Mr. Sharpe states that this species is an inhabitant of 
“ North-eastern Africa/’ it may be. well to add that, so far 
as I am aware, it has never been obtained to the north of the 
20 th degree of north latitude. 
With reference to the remaining species of this genus, N. 
hellicosus , I may remark that the darker portions of the plu¬ 
mage in the adult bird appear somewhat liable to fade; and 
Mr. Sharpe’s description seems to me to have been taken 
from a partially faded specimen. In a very fine adult example 
in perfect plumage, which I examined last year in the Zoolo¬ 
gical Gardens at Antwerp, all the darker portions of the 
plumage were slaty black, with the feathers of the upper 
