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Genus MOEPHNUS, Cuvier. 
Morphnus Cuvier, Reg. An. 1817,318. Type, Falco guianensis Daudin. 
“ Morphinus Fleming, 1822”, fide Gray. 
Ch.—F orm similar to that of Thrasaetus, but weaker and more slen¬ 
der. Tarsus more than twice the length of the middle toe; toes very 
short, the lateral ones about equal in length (the outer not appreciably 
longer), the hind toe decidedly shorter than the inner. Claws large, but 
greatly graduated in size, that of the hind toe exceeding its digit, the 
outer much less than half its length. Scutellation of the feet much 
more distinct and regular than iu Thrasaetus , the tarsus having distinct 
and continuous frontal and posterior rows of broad, regular, transverse 
scutelhe, and those of the toes uninterrupted nearly to the base; those 
on the outer side of the tarsus, between the frontal and posterior series, 
are larger than those on the inner side. Wings and tail as in Thrasaetus , 
but the latter longer and more rounded. Plumage generally the same, 
but occupital crest composed of narrower feathers. 
The genera Thrasaetus and Morphnus have so many characters in 
common, while in the same they differ so much from all the Falconidce 
more nearly related to them in other respects, that they may be considered 
as forming a group by themselves, which may be designated by the term 
Morphni. They are very closely related to the Spizaeti, to which Thra¬ 
saetus exhibits a very close approach through the equally large and 
powerful African species S. bellicosus and S. coronatus , which, with the 
present bird, constitute the largest and most powerful eagles in the 
world. It is a question whether the African species just named are not 
in reality more nearly related to Thrasaetus than to the smaller Spizaeti ; 
but this we cannot decide at present, having no specimens of either ar 
hand. The two genera under consideration differ, however, from all 
the Spizaeti , including the species above named, in the nudity of the 
tarsus, which, instead of being densely feathered all round, as in Aquila , 
is feathered only on the upper portion in front, the rest being roughly 
scaled, with larger scutellm before and behind. The “group Morphni ,” 
composed of these two genera alone, may be characterized as follows:— 
Ch.—T arsus naked, except for the upper half, or less, of the frontal 
portion, roughly scaled, the smaller scutelhe being irregularly hexago¬ 
nal, the larger forming a frontal and a posterior series; those behind 
often irregularly twisted or contorted. Toes very short, the middle one 
less than two-thirds the tarsus, the lateral ones shorter and equal; pos¬ 
terior and inner toes short and very robust, armed with powerful claws 
equal to or exceeding their digits in length, and outer toe very weak, 
with a claw less than half the length of the posterior one. Nostril broadly 
oval, obliquely vertical, the anterior side gradually beveled off' to the 
edge of the cere.* Primaries very short, scarcely exceeding the greatly- 
developed and broad secondaries; fourth or fifth quills longest, first 
shortest; their inner webs very slightly sinuated, the sinuation being 
perceptible on the sixth, or seventh, or even the eighth quill. • Tail very 
long, three-fourths or four-fifths the wing, even, or slightly rounded. 
Feathers of the occiput elongated into a conspicuous depressed crest of 
broad round-tipped feathers, and feathers of the neck developed into an 
* It is onr impression that the nostril is similarly formed in “ Spizaetus” coronatus and 
S. bellicosus; but we have no specimens for examination, and therefore cannot be 
positive. 
